Interventions for preventing excessive weight gain during pregnancy

  • Review
  • Intervention

Authors


Abstract

Background

Excessive weight gain during pregnancy is associated with multiple maternal and neonatal complications. However, interventions to prevent excessive weight gain during pregnancy have not been adequately evaluated.

Objectives

To evaluate the effectiveness of interventions for preventing excessive weight gain during pregnancy and associated pregnancy complications.

Search methods

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (20 October 2011) and MEDLINE (1966 to 20 October 2011).

Selection criteria

All randomised controlled trials and quasi-randomised trials of interventions for preventing excessive weight gain during pregnancy.

Data collection and analysis

We assessed for inclusion all potential studies we identified as a result of the search strategy. At least two review authors independently assessed trial quality and extracted data. We resolved discrepancies through discussion. We have presented results using risk ratio (RR) for categorical data and mean difference for continuous data. We analysed data using a fixed-effect model.

Main results

We included 28 studies involving 3976 women; 27 of these studies with 3964 women contributed data to the analyses. Interventions focused on a broad range of interventions. However, for most outcomes we could not combine data in a meta-analysis, and where we did pool data, no more than two or three studies could be combined for a particular intervention and outcome. Overall, results from this review were mainly not statistically significant, and where there did appear to be differences between intervention and control groups, results were not consistent. For women in general clinic populations one (behavioural counselling versus standard care) of three interventions examined was associated with a reduction in the rate of excessive weight gain (RR 0.72, 95% confidence interval 0.54 to 0.95); for women in high-risk groups no intervention appeared to reduce excess weight gain. There were inconsistent results for mean weight gain (reported in all but one of the included studies). We found a statistically significant effect on mean weight gain for five interventions in the general population and for two interventions in high-risk groups.

Most studies did not show statistically significant effects on maternal complications, and none reported significant effects on adverse neonatal outcomes.

Authors' conclusions

There is not enough evidence to recommend any intervention for preventing excessive weight gain during pregnancy, due to the significant methodological limitations of included studies and the small observed effect sizes. More high-quality randomised controlled trials with adequate sample sizes are required to evaluate the effectiveness of potential interventions.

Résumé scientifique

Interventions pour prévenir la prise de poids excessive pendant la grossesse

Contexte

La prise excessive de poids durant la grossesse est associée à de multiples complications maternelles et néonatales. Cependant, les interventions visant à prévenir la prise excessive de poids pendant la grossesse n'ont pas été suffisamment évaluées.

Objectifs

Évaluer l'efficacité des interventions destinées à prévenir la prise excessive de poids pendant la grossesse et les complications de la grossesse qui y sont associées.

Stratégie de recherche documentaire

Nous avons effectué une recherche dans le registre d’essais cliniques du groupe Cochrane sur la grossesse et la naissance (20 octobre 2011) et dans MEDLINE (de 1966 jusqu'au 20 octobre 2011).

Critères de sélection

Tous les essais contrôlés randomisés et quasi-randomisés d'interventions destinées à prévenir la prise excessive de poids pendant la grossesse.

Recueil et analyse des données

Nous avons évalué pour inclusion toutes les études potentielles identifiées au moyen de la stratégie de recherche documentaire. Au moins deux auteurs ont, de façon indépendante, évalué la qualité des essais et extrait les données. Les divergences ont été résolues par la discussion. Nous avons présenté les résultats au moyen du risque relatif (RR) pour les données catégorielles et de la différence moyenne pour les données continues. Nous avons analysé les données au moyen d'un modèle à effet fixe.

Résultats principaux

Nous avons inclus 28 études portant au total sur 3 976 femmes ; 27 de ces études, soit 3 964 femmes, ont fourni des données pour les analyses. Un large éventail d'interventions était couvert. Toutefois, pour la plupart des critères de jugement nous ne pouvions pas combiner les données dans une méta-analyse, et même lorsque nous avons pu regrouper des données, seules deux ou trois études pouvaient être combinées pour une intervention et un critère de jugement particuliers. Au total, les résultats de cette revue n'étaient généralement pas statistiquement significatifs et là où il semblait y avoir des différences entre les groupes d'intervention et de contrôle les résultats n'étaient pas cohérents. Chez les femmes des populations cliniques générales, une des trois interventions examinées (counseling comportemental comparé aux soins standard) était associée à une réduction du taux de prise de poids excessive (RR = 0,72 ; intervalle de confiance à 95 % 0,54 à 0,95) ; pour les femmes appartenant à des groupes à haut risque aucune intervention n'avait semblé réduire la prise de poids excessive. Les résultats concernant la prise de poids moyenne (rapportée dans toutes les études incluses, sauf une) étaient contradictoires. Nous avons trouvé un effet statistiquement significatif sur la prise moyenne de poids pour cinq interventions dans la population générale et pour deux interventions dans les groupes à haut risque.

La plupart des études n'avaient pas constaté d'effets statistiquement significatifs sur les complications maternelles et aucune n'avait fait état ​​d'effets significatifs sur les résultats néonataux indésirables.

Conclusions des auteurs

Les données récoltées ne permettent pas de recommander une quelconque intervention visant à prévenir la prise de poids excessive pendant la grossesse, en raison des importantes limitations méthodologiques des études incluses et de la petite taille des effets observés. Il faudra réaliser de nouveaux essais contrôlés randomisés de bonne qualité, avec des effectifs suffisamment nombreux, afin d'évaluer l'efficacité d'interventions potentielles.

アブストラクト

妊娠中の過剰な体重増加の予防に対する介入

背景

妊娠中の過剰な体重増加は、母体と新生児の複数の合併症に関連している。しかし、妊娠中の過剰な体重増加を予防するための介入について、十分な評価は実施されていない。

目的

妊娠中の過剰な体重増加と、その関連する妊娠合併症を予防する介入の有効性を評価すること。

検索戦略

Cochrane Pregnancy and Childbirth Group's Trials Register(2011年10月20日)およびMEDLINE(1966~2011年10月20日)を検索した。

選択基準

妊娠中の過剰な体重増加を予防する介入についての、すべてのランダム化比較試験(RCT)および準ランダム化試験

データ収集と分析

検索戦略の結果、同定したすべての研究について選択可能か評価した。2名以上のレビューアが別々に試験の質を評価し、データを抽出した。不一致は討議により解決した。カテゴリデータにはリスク比(RR)を、連続データには平均差を用いて結果を提示した。固定効果モデルを用いてデータを解析した。

主な結果

女性3,976名を対象とした28件の研究を選択し、これらの研究のうち27件、女性3,964名が解析対象データとなった。着目された介入は、広範囲にわたっていた。しかし、大半のアウトカムではメタアナリシスでデータを統合できず、データをプールした場合でも特定の介入およびアウトカムについて、2~3件の研究しか統合できなかった。全体として、本レビューの結果は概して統計学的に有意ではなく、介入群とコントロール群で差があるような場合でも一貫した結果はみられなかった。一般診療所対象集団の女性では、検討された3つの介入のうち1つ(行動カウンセリングと標準治療との比較)は、過剰な体重増加率の低下と関連していた(RR 0.72、95%信頼区間0.54~0.95)。ハイリスク群の女性では、過剰な体重増加を減少させた介入はみられなかった。平均体重増加量の結果は一貫していなかった(1件以外すべての選択した研究で報告があった)。一般集団では5つの介入で、ハイリスク群では2つの介入で平均体重増加への統計学的に有意な効果が認められた。 大半の研究では母体合併症に統計学的に有意な効果を示さず、新生児の有害なアウトカムへの有意な影響の報告はなかった。

著者の結論

選択した研究の重大な方法論的限界および観察された効果サイズの小ささのため、妊娠中の過剰な体重増加を予防する何らかの介入を推奨するに足るエビデンスは認められなかった。可能性のある介入の有効性を評価するため、十分なサンプル・サイズの高品質のランダム化比較試験(RCT)が必要である。

Plain language summary

Interventions for preventing excessive weight gain during pregnancy

A large proportion of women gain more weight than is recommended during pregnancy. Excessive weight gain increases the risk of complications for both the mother and her infant. These include miscarriage, development of diabetes mellitus or pregnancy-induced hypertension, a high birthweight infant and the likelihood of caesarean section. We reviewed 28 randomised controlled studies that involving more than 3000 women, mostly from developed countries, to assess the effectiveness of interventions for preventing excessive weight gain during pregnancy (27 of the studies with 3964 women contributed data to the analyses). Results on preventing excessive weight gain during pregnancy were limited to studies that included this as an outcome. There were five interventions in the general population and two interventions in high-risk groups which seemed to reduce average weight gain during pregnancy. Few studies looked at excessive weight gain during pregnancy and only one of the interventions they used resulted in significantly reduced rates of excessive weight gain. It is not appropriate for us to recommend any one intervention for preventing excessive weight gain during pregnancy because most of the studies identified were of poor quality and the effects of the interventions were generally small. There is an urgent need for more well-designed studies with adequate sample sizes to be able to recommend effective interventions.

Résumé simplifié

Interventions pour prévenir la prise de poids excessive pendant la grossesse

Une grande proportion de femmes prend durant leur grossesse plus de poids qu'il n'est recommandé. La prise de poids excessive accroit le risque de complications tant pour la mère que pour l'enfant : fausse couche, développement d'un diabète sucré ou d'une hypertension gravidique, poids de naissance élevé pour le nourrisson et probabilité d'avoir à subir une césarienne. Nous avons examiné 28 études contrôlées randomisées impliquant au total plus de 3 000 femmes, pour la plupart de pays développés, afin d'évaluer l'efficacité des interventions destinées à éviter la prise de poids excessive pendant la grossesse (27 de ces études, soit 3 964 femmes, ont fourni des données pour les analyses). Les résultats sur la prévention de la prise de poids excessive pendant la grossesse se limitaient aux études qui l'avaient inclus comme critère de jugement. Il y avait cinq interventions dans la population générale et deux interventions dans des groupes à risque qui semblaient réduire la prise moyenne de poids pendant la grossesse. Peu d'études avaient examiné la prise de poids excessive pendant la grossesse et une seule des interventions utilisées avait conduit à une baisse significative des taux de prise de poids excessive. Nous ne pouvons recommander aucune intervention de prévention de la prise de poids excessive pendant la grossesse parce que la plupart des études identifiées étaient de mauvaise qualité et que les effets des interventions étaient généralement faibles. Il y a un besoin urgent de nouvelles études bien conçues avec des effectifs de tailles suffisantes afin de pouvoir recommander des interventions efficaces.

Notes de traduction

Traduit par: French Cochrane Centre 1st June, 2012
Traduction financée par: Ministère du Travail, de l'Emploi et de la Santé Français

平易な要約

妊娠中の過剰な体重増加の予防に対する介入

女性の大多数は、妊娠中に推奨されている以上の体重増加を示す。過剰な体重増加により、母親と児の双方の合併症リスクが上昇する。リスクとして、流産、糖尿病の発症、妊娠に誘発された高血圧の発症、高出生体重児や帝王切開の可能性などがある。大半は先進国からの3,000名超の女性を対象とした28件のランダム化比較研究をレビューし、妊娠中の過剰な体重増加を予防する介入の有効性を評価した(3,964名の女性を対象とした27件の研究を解析した)。妊娠中の過剰な体重増加の予防に関する結果は、これをアウトカムとして含んでいる研究に限定されていた。妊娠中の平均体重増加を減少させると考えられる介入は、一般集団では5つ、ハイリスク群では2つ認められた。妊娠中の過剰な体重増加について観察した研究はほとんどなく、用いられた介入のうち1つのみが過剰な体重増加の率を有意に低下させた。同定した研究の大半は質が低く、介入の効果は概して小さかったため、妊娠中の過剰な体重増加を予防するためのいずれの介入も推奨することはできない。有効性の高い介入を推奨するには、十分なサンプル・サイズの適切なデザインの研究が緊急に必要である。

訳注

監  訳: 江藤 宏美,2012.8.29

実施組織: 厚生労働省委託事業によりMindsが実施した。

ご注意 : この日本語訳は、臨床医、疫学研究者などによる翻訳のチェックを受けて公開していますが、訳語の間違いなどお気づきの点がございましたら、Minds事務局までご連絡ください。Mindsでは最新版の日本語訳を掲載するよう努めておりますが、編集作業に伴うタイム・ラグが生じている場合もあります。ご利用に際しては、最新版(英語版)の内容をご確認ください。

Background

Description of the condition

Pregnancy weight gain guidelines

In 2009, the Institute of Medicines (IOM) in the United States updated earlier guidelines on weight gain during pregnancy (Medicine 1990; Medicine 2009). The report set out specific ranges of weight gain for women with different prepregnancy weights: suggesting that underweight women (body mass index (BMI) less than 18.5 kg/m²) gain 28 to 40 lbs (12.5 kg to 18 kg); normal weight women (BMI 18.5 kg/m² to 24.9 kg/m²) gain 25 to 35 lbs (11.5 kg to 16 kg); whereas overweight women (BMI 25 kg/m² to 29.9 kg/m²) were advised to gain between 15 and 25 lbs (7 to 11.5 kg) and obese women (BMI at least 30 kg/m²) to gain between 11 and 20 lbs (5 to 9 kg) (Medicine 2009).

Previous guidelines from the IOM (Medicine 1990) had been widely adopted but not universally accepted. However, a review of relevant information confirmed that pregnancy weight gain within the IOM's recommended ranges was associated with the best outcomes for both mothers and infants, and that weight gain within the IOM's recommended ranges is not harmful for the mothers or for their infants (Abrams 2000).

No official recommendations or clinical guidelines for weight gain during pregnancy exist in the United Kingdom (UK) (Ford 2001). However, a recent report from the UK Centre for Maternal and Child Enquiries (CMACE 2010) suggested a more comprehensive guidance for the care of overweight and obese women, and recommended weighing women in the third trimester and again when women are admitted in labour. Guidelines in other countries have also recommended monitoring weight gain in pregnancy. The optimal gestational weight gain in Swedish women was 4 kg to 10 kg for BMI less than 20; 2 kg to 10 kg for BMI 20 to 24.9. For women with a BMI of 25 to 29.9, a weight gain of less than 9 kg was recommended, and pregnant women with a BMI of 30 or more were recommended to gain less than 6 kg in weight (Cedergren 2007). Pregnant Asian women in general had lower weight gains in comparison to pregnant women in Europe and North America (Abrams 1995; Siega-Riz 1993). Hence, maternal weight gain recommendations based on data from high-income countries may not be applicable to Asian women. A study to produce ethnic-specific maternal weight gain recommendations was performed in China. The recommended total weight gain was 13 kg to 16.7 kg, 11 kg to 16.4 kg, and 7.1 kg to 14.4 kg respectively for women of low (BMI less than 19), moderate (BMI 19 to 23.5), and high (BMI greater than 23.5) BMI measurement (Wong 2000).

Trends in pregnancy weight gain

Although the 1990 IOM guidelines have now been promoted for two decades it has been estimated that over this time only 30% to 40% of pregnant women in the United States gain gestational weight within the IOM recommended ranges (Abrams 2000; Cogswell 1999; Medicine 1990; Olson 2003). Furthermore, gestational weight gain above the guidelines is more common than gestational weight gain below (Stotland 2006). Several studies on gestational weight gain in the USA and Europe indicate that about 20% to 40% of women are gaining weight above the recommendations (Cedergren 2006; Medicine 2009; Olson 2003) and the prevalence of excessive gestational weight gain is increasing (Abrams 2000; Rhodes 2003; Schieve 1998). A retrospective cohort study undertaken to examine the trend in weight gain during pregnancy of 1,463,936 women over 16 years in North Carolina found that the proportion of women gaining excessive gestational weight (more than 18 kg) increased from 15.5% in 1988 to 19.5% in 2003; an additional 40 women per 1000 gained excessive weight by 2003 (Helms 2006). The recent IOM report summarised the situation in a number of countries; compared with two decades earlier "Women today are also heavier; a greater percentage of them are entering pregnancy overweight or obese, and many are gaining too much weight during pregnancy" (Medicine 2009).

Weight gain during pregnancy is generally inversely proportional to prepregnancy weight category. Overall, underweight women were least likely to exceed weight gain recommendations although obese women tended to gain less weight than normal and over-weight women (Abrams 1989; Bianco 1998; Edwards 1996; Walling 2006). For instance, two large population-based studies, in Sweden and the United States, reported similar findings. They found that approximately 30% of average and overweight women had high gestational weight gain, whereas approximately 20% of obese women had high gestational weight gain (Cedergren 2006; Cogswell 1995).

Pregnancy weight gain and outcomes for mothers and infants

It is well known from large studies in a number of countries that excessive weight gain during pregnancy is associated with multiple maternal and neonatal complications. Retrospective cohort studies have examined the relationship between gestational weight gain and adverse neonatal outcomes among infants born at term. It was established that gestational weight gain above the upper limit of the IOM guideline was associated with a low five-minute Apgar score, seizure, hypoglycaemia, polycythaemia, meconium aspiration syndrome and large-for-gestational age compared with women within weight gain guidelines (Hedderson 2006; Stotland 2006). Obese women with low gestational weight gain had a decreased risk for the following outcomes: pre-eclampsia, caesarean section, instrumental delivery, and large-for-gestational age births, whereas, excessive weight gain of obese women increased the risk for caesarean delivery in all maternal BMI classes (Cedergren 2006).

Findings from a national study in the UK revealed that compared with pregnant women in general, obese pregnant women were at increased risk of having a co-morbidity diagnosed before or during pregnancy (in particular pregnancy-induced hypertension and gestational diabetes), were more at risk of having induction of labour and a caesarean birth, were more likely to have postpartum haemorrhage and their babies were at increased risk of stillbirth, neonatal death, of being large for gestational age and more likely to be admitted for special care (CMACE 2010).

There have been a number of studies which conclude that excessive gestational weight gain increases postpartum weight retention (Gunderson 2000; Keppel 1993; Polley 2002; Rooney 2002; Rossner 1997; Scholl 1995) and is related to a two- to three-fold increase in the risk of becoming overweight after delivery (Gunderson 2000). Moreover, mothers who gained more weight during pregnancy had children at higher risk of being overweight in early childhood (Oken 2007).

However, to be too strict in weight gain restriction might not have the expected result. It was established that in three trials involving 384 women, energy or protein restriction of pregnant women who were overweight or exhibited high weight gain significantly reduced weekly maternal weight gain and reduced mean birthweight but had no effect on pregnancy-induced hypertension or pre-eclampsia. It concluded that protein or energy restriction of pregnant women is unlikely to be beneficial and may be harmful to the infant (Kramer 2003).

Description of the intervention

Dietary control, exercise and eating behaviour modification are the main elements for controlling weight. Pregnancy may be an optimal time to inform and challenge women to change their eating habits and physical activities, and thereby prevent excessive weight gain.

How the intervention might work

There are systematic reviews which aimed to assess the effect of dietary advice, exercise intervention and psychosocial intervention for achieving weight loss in overweight and obese adults. The results of Cochrane review on exercise for overweight or obesity support the use of exercise as a weight loss intervention, particularly when combined with dietary change (Shaw 2006). People who are overweight or obese may benefit from psychological interventions, particularly behavioural and cognitive-behavioural strategies, to enhance weight reduction. The evidence suggests that these measures are predominantly useful when combined with dietary and exercise strategies (Shaw 2005). In addition, overall, weight loss strategies using dietary, physical activity, or behavioural interventions produced significant improvement in weight among people with prediabetes (Norris 2005).

Why it is important to do this review

Given the increasing prevalence and negative consequences of excessive gestational weight gain, preventing excessive weight gain during pregnancy is potentially important. Intervention might help pregnant women to achieve the recommended weight gain, with the objective of ensuring the best possible outcome for their infants and themselves. Although there are Cochrane reviews evaluating the effect of dietary advices, exercise, and psychological interventions on controlling weight, there are no systematic review evaluating interventions for controlling excessive weight gain during pregnancy.

The aim of this review is to identify and systematically review all randomised controlled trials of interventions for limiting weight gain during pregnancy to provide the best available evidence for clinical decision-making and to stimulate further research about preventing excessive weight gain during pregnancy.

Objectives

To evaluate the effectiveness of interventions for preventing excessive weight gain during pregnancy and associated pregnancy complications.

Methods

Criteria for considering studies for this review

Types of studies

We have included all randomised controlled trials (RCTs) and quasi-RCTs of interventions aimed at preventing excessive weight gain during pregnancy, irrespective of their country of origin or language.

Types of participants

Pregnant women.

Types of interventions

Any intervention (e.g. nutrition intervention, exercise intervention, health education or counselling) for preventing excessive weight gain compared with routine care or other interventions for preventing excessive weight gain in pregnancy.

Types of outcome measures

Primary outcomes

Excessive weight gain as defined by trialists.

Secondary outcomes
For the mothers
  1. Weight gain.

  2. Low weight gain as defined by trialists.

  3. Preterm birth.

  4. Preterm prelabour rupture of membranes.

  5. Pre-eclampsia or eclampsia.

  6. Need for and indication for induction of labour.

  7. Caesarean delivery.

  8. Postpartum complication including postpartum haemorrhage, wound infection, endometritis, need for antibiotics, perineal trauma, thromboembolic disease, maternal death.

  9. Behaviour modification outcomes: diet, physical activity.

For the newborns
  1. Birthweight greater than 4000 gm or greater than the 90th centile for gestational age and infant sex.

  2. Birthweight less than 2500 gm or less than the 10th centile for gestational age and infant sex.

  3. Complication related to macrosomia including hypoglycaemia, hyperbilirubinaemia, infant birth trauma (palsy, fracture, shoulder dystocia).

Long-term health outcomes
  1. Maternal weight retention postpartum.

  2. Childhood weight.

Search methods for identification of studies

Electronic searches

We contacted the Trials Search Co-ordinator to search the Cochrane Pregnancy and Childbirth Group’s Trials Register (20 October 2011).

The Cochrane Pregnancy and Childbirth Group’s Trials Register is maintained by the Trials Search Co-ordinator and contains trials identified from:

  1. quarterly searches of the Cochrane Central Register of Controlled Trials (CENTRAL);

  2. weekly searches of MEDLINE;

  3. weekly searches of EMBASE;

  4. handsearches of 30 journals and the proceedings of major conferences;

  5. weekly current awareness alerts for a further 44 journals plus monthly BioMed Central email alerts.

Details of the search strategies for CENTRAL and MEDLINE, the list of handsearched journals and conference proceedings, and the list of journals reviewed via the current awareness service can be found in the ‘Specialized Register’ section within the editorial information about the Cochrane Pregnancy and Childbirth Group.

Trials identified through the searching activities described above are given a code (or codes) depending on the topic. The codes are linked to review topics. The Trials Search Co-ordinator searches the register for each review using these codes rather than keywords.

In addition, we searched MEDLINE (1966 to 20 October 2011) using the search strategy given in Appendix 1

We did not apply any language restrictions.

Data collection and analysis

Selection of studies

Two review authors independently assessed for inclusion all the potential studies we identified as a result of the search strategy. We resolved any disagreement through discussion and where necessary, by involving a third author.

Data extraction and management

We designed a form to extract data. For eligible studies, two review authors extracted data using the agreed form. We resolved discrepancies through discussion and where necessary, by involving a third author. We entered data into Review Manager software (RevMan 2011) and checked for accuracy.

When information regarding any of the above was unclear, we attempted to contact authors of the original studies to provide further details.

Assessment of risk of bias in included studies

Two review authors independently assessed risk of bias for each study in six domains (sequence generation, allocation concealment, blinding, incomplete outcome data, selective reporting bias, and other sources of bias) using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). We resolved any disagreement by discussion or by involving a third author.

Measures of treatment effect

For dichotomous data, we presented results as summary risk ratio with 95% confidence intervals. 

For continuous data, we used the mean difference if outcomes were measured in the same way between trials. We planned to use the standardised mean difference to combine trials that measured the same outcome, but used different methods.

Unit of analysis issues

We included a cluster-randomised trial in the analyses (Luoto 2011) along with individually- randomised trials. We adjusted their sample sizes and event rates using an intraclass correlation coefficient (ICC) of 0.12 estimated by the trial authors and published in Luoto 2010.

Dealing with missing data

The missing standard deviations were imputed from 95% confidence intervals or standard errors. We have reported the results of some included studies in the additional tables when the missing data could not be imputed.

Assessment of heterogeneity

Where we pooled studies in meta-analysis, we assessed statistical heterogeneity in each meta-analysis using the I² statistic. We regarded heterogeneity as substantial if I² was greater than 50% (Higgins 2011).

Assessment of reporting biases

We did not generate funnel plots to assess possible publication bias for the primary outcome because there were not enough studies in each comparison (fewer than 10 studies).

Data synthesis

We carried out statistical analysis using the Review Manager software (RevMan 2011). We used a fixed-effect model to pool studies to produce summary statistics when the I² was less than 50%. On the other hand, when I² was greater than 50%, we repeated the analysis using a random-effects model. We have indicated in the results text when we have used a random-effects model as the pooled result represents an average treatment effect and, in the presence of high heterogeneity, such results should be interpreted with caution.

However, in this version of the review, for most outcomes we could not combine data in a meta-analysis, and where we did pool data,no more than two studies could be combined for a particular intervention and outcome.

Subgroup analysis and investigation of heterogeneity

For our primary outcome we had planned to carry out subgroup analysis by:

  1. prepregnancy BMI: (1) underweight (2) normal weight (3) overweight (4) obese (as defined by trialists);

  2. gestational age at first visit prenatal clinic: (1) 20 weeks or less; or (2) more than 20 weeks;

  3. gestational age at first visit prenatal clinic: (1) 28 weeks or less; or (2) more than 28 weeks.

Gestational age at 28 weeks (early in the third trimester) is the stage at which weight gain is rapidly increasing.

After examining the interventions offered to different population subgroups, we decided that rather than carrying out subgroup analysis by prepregnancy BMI we would present results for women drawn from the general population (and including all weight categories) and high-risk groups (including women with, or at high risk of, gestational diabetes and/or who were overweight or obese at recruitment) in separate comparisons. We made this decision as the clinical management of women in high-risk groups is likely to be different, and the interventions offered to these women were designed specifically to address their high-risk status.

For other subgroup analysis, in this version of the review, we did not carry out planned subgroup analyses, due to insufficient studies contributing data for the primary outcome (a maximum of three studies provided data for our primary outcome in each comparison). We included one cluster trial but again, there were not enough studies to carry out subgroup analysis by studies using different units of randomisation. In future updates if more data become available for existing comparisons, we will carry out planned analysis for the review's primary outcomes and, where appropriate, we will carry out the subgroup interaction tests available in RevMan 2011.

Sensitivity analysis

We did not carry out sensitivity analysis because only two included studies were combined for the primary outcome.

Results

Description of studies

See: Characteristics of included studies; Characteristics of excluded studies; Characteristics of studies awaiting classification; Characteristics of ongoing studies.

See Characteristics of included studies; Characteristics of excluded studies; Characteristics of studies awaiting classification; Characteristics of ongoing studies.

Results of the search

The search strategies described above identified 63 potential studies. Following application of eligibility criteria, we included 28 studies in this review. We excluded 12 studies. Two studies are currently awaiting assessment (we have contacted authors for more information) and the other 21 studies are ongoing.

Included studies

From 28 included studies, two studies were quasi-RCTs (Bechtel-Blackwell 2002; Moses 2006); one study was a cluster-RCT (Luoto 2011); the remaining studies were RCTs.

Participants: the 28 included studies involved 3976 participants, although one of these studies (with 12 women) did not report on any of the review's outcomes and has not contributed data to the review (Magee 1990) (we have included information about this trial in the Characteristics of included studies tables, but it is not otherwise discussed in the remaining sections below). Therefore, our findings are based on 27 studies with 3964 participants. The number of participants in each study varied from 20 to more than 300. The age of participants ranged from 25 to 49 years, except for one study (Bechtel-Blackwell 2002) which included adolescent women aged 13 to 18 years.

Settings: two trials (Santos 2005; Vitolo 2011) were conducted in Brazil. One trial (Huang 2011) was conducted in Taiwan. All others were conducted in developed countries: Australia, Belgium, Canada, Denmark, Finland, Spain and the United States of America; however, two of these studies (Hui 2006; Polley 2002) recruited women with low, or low-middle incomes.

Interventions: most of the interventions considered in this review focused on modifying diet and increasing exercise, however, there was considerable variation in the interventions and in the care received by control groups. Interventions included dietary counselling, dietary intervention (e.g. provision of dietary supplements or foodstuffs), exercise counselling, exercise interventions (e.g. supervised exercise sessions), nutritional monitoring, regular weight measurement, computer-assisted self-interview, and the use of an appetite suppressant drug. These interventions varied in intensity and may have involved more than one approach. Interventions were compared with standard care (which again varied considerably in different settings and was not always well-described) or with another type of intervention. Some studies included more than two arms and these studies may be included in more than one comparison.

Outcomes: only five of the 27 included studies contributing data reported excessive weight gain during pregnancy as a primary outcome. Other studies reported other outcomes, but in all studies except the trial by Callaway 2010, weight gain was reported as one of the outcomes. Some studies reported low weight gain as a outcome. Other outcomes reported included maternal complications and adverse neonatal outcomes.

Only one study (Thornton 2009) reported on postpartum complication outcomes such as postpartum haemorrhage, wound infection, endometritis, need for antibiotics, perineal trauma, thromboembolic disease, or maternal death.

We have reported results separately for pregnant women drawn from the general population (and which may include overweight and obese women) and for known high-risk groups. Of the 27 studies contributing data, 13 specifically recruited women from high-risk groups (i.e. women who were all overweight or obese at recruitment, or women at high risk of gestational diabetes due to weight or other risk factors). Ten studies recruited women from the general pregnant population and results for high- and low-risk women were not reported separately. In four studies (Jeffries 2009; Phelan 2011; Polley 2002; Vitolo 2011), women in all weight categories were recruited, but findings were reported separately for women with low/normal versus overweight/obese prepregnancy weights; therefore, relevant findings from these four studies are reported in both comparisons.

Studies recruiting women in high-risk groups: there were differences in the prepregnancy weight of women recruited to studies; only women who were overweight or obese were recruited in studies by Callaway 2010; Guelinckx 2010; Quinlivan 2011; Rhodes 2010; Santos 2005; Thornton 2009; Wolff 2008; women who were either considered overweight or appeared to be gaining excessive weight in early pregnancy were recruited by Boileau 1968 and Silverman 1971. Women with or at high risk of gestational diabetes were included in four studies (Korpi-Hyovalti 2011; Luoto 2011; Moses 2009; Rae 2000) A mix of underweight, normal, overweight, and obese women were included in studies by Jeffries 2009; Phelan 2011; Polley 2002; Vitolo 2011 with separate results provided for women in the overweight/obese groups.

Interventions in these studies included:

Studies recruiting women in all weight categories: 10 studies included women in all weight categories (Asbee 2009; Barakat 2011; Bechtel-Blackwell 2002; Clapp 2002; Clapp 2002a; Huang 2011; Hui 2006; Jackson 2011; Laitinen 2009; Moses 2006) and as we have mentioned above, four studies reported findings for under and normal weight women separately (Jeffries 2009; Phelan 2011; Polley 2002; Vitolo 2011).

Interventions in these studies varied considerably and the comparison conditions also differed. Interventions included:

Excluded studies

We excluded 12 studies. We excluded seven studies for the following reasons: participants included both pregnant and nonpregnant women (two studies); participants were not pregnant (postpartum or other non-pregnant participants) (four studies); or the intervention was not relevant (one study). The remaining five studies were not RCTs.

Risk of bias in included studies

Details of the methodological quality of each study are given in Characteristics of included studies, Figure 1, and Figure 2.

Figure 1.

Methodological quality summary: review authors' judgements about each methodological quality item for each included study.

Figure 2.

Methodological quality graph: review authors' judgements about each methodological quality item presented as percentages across all included studies.

Allocation

Seventeen out of 27 included studies contributing data were assessed as being at low risk of bias for generation of the randomisation sequence and 12 used methods that we judged were at low risk of bias for allocation concealment. Three studies were assessed to use methods at high risk of bias for allocation concealment. The remaining studies were unclear for allocation concealment.

Blinding

Ten out of 27 studies had taken some steps to implement blinding. Acheiving blinding of treatment allocation for diet and exercise interventions is, however, not feasible and for most studies it was difficult to ascertain whether the lack of blinding, or unsuccessful blinding, impacted on outcomes or resulted in any systematic bias.

Incomplete outcome data

Fourteen of the studies either had relatively low levels of attrition or had carried out intention-to-treat analysis. Seven studies had a high rate of loss to follow-up. In the remaining studies, loss of outcome data was unclear.

Selective reporting

It was difficult to assess bias associated with the outcome reporting bias as we did not have access to study protocols and we did not know whether results for all outcomes where data had been collected had been reported; we therefore assessed most of these studies as being unclear for the outcome reporting bias.

Other potential sources of bias

We have reported in the Characteristics of included studies tables where we noted any obvious other sources of bias (such as clear differences between groups at baseline).

Effects of interventions

Our findings are based on data from 27 studies with 3964 women. Some studies had more than two arms and may have been included in more than one comparison and four studies reported data separately for high- and low-risk groups and relevant data have been included in more than one comparison. One study (Luoto 2011) was a cluster-randomised trial, and in the analyses we adjusted the sample size and event rates for this study by using an ICC from Luoto 2010. We have set out the original data from the Luoto 2011 study in Table 1 and Table 2.

Table 1. The original data and adjusted data of continuous data of the cluster-randomised trial (Luoto 2011)
  1. 1 M = average cluster size = ((total number of intervention + total number of control)/(cluster number of intervention + cluster number of control)

    2 ICC = intraclass correlation; obtained from the reliable external source (Luoto 2010).

    3 Design effect = 1 + (M-1)/ICC

    4 Adjusted sample sizes = n / design effect

OutcomeIntervention (Original data)Control (Original data)M1ICC2Design effect3Adjusted sample4 sizes

Cluster

number

Total numberx̄ ± SD

Cluster

number

Total numberx̄ ± SDInterventionControl
Maternal Weight gain721613.8±5.8717914.2±5.128.210.124.2750.6441.96
Table 2. The original data and adjusted data for dichotomous data of the cluster-randomised trial (Luoto 2011)
  1. 1 M = average cluster size = (total number of intervention + total number of control)/(cluster number of intervention + cluster number of control)

    2 ICC = intraclass correlation; obtained from the reliable external source (Luoto 2010).

    3 Design effect = 1 + (M-1)/ICC

    4 Adjusted data = n / design effect

OutcomesIntervention (Original data)Control (Original data)M1ICC2Design effect3Intervention (Adjusted data)4Control(Adjusted data)4

Cluster

number

Total numbern

Cluster

number

Total numberntotal numberntotal numbern
Pre-eclampsia72161471791028.210.124.2750.643.2841.962.34
Birthweight > 4000 grams72163771793628.210.124.2750.648.6741.968.44
Infant birthweight > 90th centile72162671793428.210.124.2750.646.1041.967.97
Infant birthweight < the 10th centile7216107179528.210.124.2750.642.3441.961.17

For most outcomes only one or two studies provided outcome data. Where outcome data were available for studies examining different types of diet and exercise or weight monitoring interventions, we have presented findings in a single forest plot (with the different interventions separated into subgroups) but, due to differences in the interventions examined, we have not pooled the results for different types of interventions in the meta-analysis and report subtotals only.

1. Interventions to prevent excessive weight gain versus standard care or routine care (interventions in general population groups) (nine trials)

Primary outcome
1.1 Excessive weight gain

This outcome was reported in four trials including a total of 444 women examining three different types of interventions. Trials comparing regular weight management (Jeffries 2009) and a diet and exercise intervention (Hui 2006) showed no significant differences between groups (risk ratio (RR) 0.57, 95% confidence interval (CI) 0.23 to 1.40, and, RR 0.63, 95% CI 0.23 to 1.68 respectively). Two studies with 247 women (Phelan 2011; Polley 2002) showed a positive treatment effect associated with behavioural counselling compared with standard care (RR 0.72, 95% CI 0.54 to 0.95, I2 = 0%) (Analysis 1.1).

Secondary outcomes
For the mothers
1.2 Weight gain

Weight gain was reported in nine trials. Six different interventions were examined and overall, three different types of interventions achieved positive treatment effects.

We pooled results from three trials with 341 women (Asbee 2009; Phelan 2011; Polley 2002) examining behavioural counselling. Women in the intervention group gained 1.39 kg less than controls (95% CI -2.48 to -0.30); there was moderate heterogeneity for this outcome (I2 = 39%). There was evidence from one trial (Barakat 2011) that an intensive intervention involving supervised exercise sessions resulted in women gaining on average 2 kg less compared with controls (95% CI -3.26 to -0.74).

Pooled results from two studies (Huang 2011; Hui 2006) examining a diet and exercise intervention also favoured the intervention group (mean difference (MD) -2.03, 95% CI -2.99 to -1.07) although the positive effect was only associated with one of the two trials (Huang 2011).

Results were not consistent however, for other interventions examined in single studies, there were no significant differences between groups: dietary counselling with the provision of probiotics (RR 0.20, 95% CI -1.22 to 1.62), dietary counselling alone (RR 0.00, 95% CI -1.53 to 1.53) and regular weight monitoring (RR -0.75, 95% CI -1.98 to 0.48) (Analysis 1.2).

1.3 Low weight gain

This outcome was reported in two trials with 247 women examining a behavioural counselling intervention (Phelan 2011; Polley 2002); there was no significant difference between groups (RR 1.33, 95% CI 0.74 to 2.37) (Analysis 1.3).

1.4 Preterm birth

Three trials examining two different interventions (regular weight management (Jeffries 2009) and behavioural counselling (Phelan 2011; Polley 2002) reported findings for preterm birth. There were no significant differences in the number of babies born prematurely for women in the intervention and control groups for either intervention (RR 0.67, 95% CI 0.15 to 2.93, and 0.75, 95% CI 0.36 to 1.58 respectively)(Analysis 1.4). There was heterogeneity for the pooled results examining behavioural counselling with an I² value of 70%. In view of heterogeneity, we repeated the analyses using a random-effects model; again, there was no evidence of a significant difference between groups (data not shown).

1.5 Pre-eclampsia

This outcome was measured in three trials and results from these trials did not demonstrate any significant differences between groups (Analysis 1.5) (regular weight management (Jeffries 2009) (RR 2.69, 95% CI 0.55 to 13.03) and behavioural counselling (Phelan 2011; Polley 2002) (RR 0.34, 95% CI 0.10 to 1.22)).

1.6 Need for and indication for induction of labour and caesarean delivery

None of the included studies with general population samples reported on the number of women requiring induction of labour. The number of women experiencing caesarean delivery was reported in five trials. There were no clear differences between groups receiving interventions involving behavioural counselling (three trials; RR 0.78, 95% CI 0.53 to 1.16), regular weight management (one trial; RR 1.22, 95% CI 0.82 to 1.82) or regular supervised exercise (one trial, 0.68, 95% CI 0.29 to 1.57) compared with controls (Analysis 1.6).

1.7 - 1.10 Behaviour modification outcomes: diet, physical activity

In a three-arm trial Laitinen 2009 examined the effects of dietary counselling with or without probiotic supplements compared with controls; there was no clear evidence that either intervention was associated with differences in reported mean energy or fibre intake compared with controls (Analysis 1.7; Analysis 1.8).

Huang 2011 in a study with 125 women and Hui 2006 in a study with 45 women both measured women's reported physical activity scores on different scales. Both studies suggested that women receiving diet and exercise interventions had higher mean activity scores than controls, and in both studies the difference between groups reached statistical significance (MD 1.63, 95% CI 0.85 to 2.41, and MD 0.48, 95% CI 0.18 to 0.78 respectively) (Analysis 1.9).

A single study with 287 women examining the effect of an interactive video counselling intervention reported on the number of women saying they exercised for 30 minutes on most days (Jackson 2011). There was no significant difference between the intervention and control groups; about a third of women in both arms of the trial reported regular exercise (RR 1.31, 95% CI 0.92 to 1.86)(Analysis 1.10).

For the newborns
1.11 - 1.14 High and low birthweight

Four studies (examining three different interventions) reported the number of babies with a birthweight above 4000 gm. None of the studies showed evidence of a significant difference between intervention groups and controls (behavioural counselling, 2 studies, RR 2.19, 95% CI 0.63 to 7.60; supervised exercise, 1 study RR 0.65, 95% CI 0.12 to 3.63; exercise plus diet intervention, 1 study RR 0.44, 95% CI 0.09 to 2.15) (Analysis 1.11). One additional study examining regular weight monitoring reported on the number of babies with birthweight above the 90th centile. Again, there was no clear difference between groups (RR 0.65, 95% CI 0.27 to 1.56) (Analysis 1.12).

Three studies reported on the number of babies with low birthweight. There was no strong evidence that interventions were associated with low infant birthweight (behavioural counselling, 2 studies RR 1.03, 95% CI 0.40 to 2.63; regular weight management, 1 study, RR 0.67, 95% CI 0.29 to 1.53) (Analysis 1.13; Analysis 1.14).

1.15 - 1.16 Complication related to macrosomia

A single study examining regular weight monitoring reported the number of babies with neonatal hypoglycaemia (Jeffries 2009); there was no clear difference between groups (RR 2.69, 95% CI 0.28 to 25.44) (Analysis 1.15). This same study reported on shoulder dystocia during the birth; again, there was no clear evidence that the intervention was associated with any difference in this birth complication (RR 0.90, 95% CI 0.06 to 14.14) (Analysis 1.16).

Long-term health outcomes
1.17 - 1.18 Maternal weight retention

A single study with a sample of 39 women (Polley 2002) reported on the mean weight retention in the postpartum period. On average, although women receiving a behavioural counselling intervention retained less weight (1.8 kg) compared with controls, there was a wide CI for this outcome and the difference between groups was not statistically significant (95% CI -4.95 to 1.35 kg) (Analysis 1.17).

The results of two trials examining different interventions; behavioural counselling intervention (Phelan 2011 with 186 women) and exercise and dietary intervention (Huang 2011 with 125 women) reported that women in intervention groups were less likely to be above their prepregnancy or early pregnancy weight at six months postpartum (RR 0.80, 95% CI 0.67 to 0.97, and RR 0.35, 95% CI 0.19 to 0.63 respectively) (Analysis 1.18).

2. Interventions to prevent excessive weight gain: alternative interventions (interventions in general population groups) (five trials)

Although six trials are included in this comparison, for many outcomes only single studies reported results and for some of our primary and secondary outcomes no studies contributed data. The study by Clapp 2002a examined different types and treatment order of exercise interventions and results for this study are reported separately for different comparison arms.

Primary outcome
Excessive weight gain

None of the studies in this comparison reported results for this outcome.

Secondary outcomes
For the mothers
2.1 Weight gain

Weight gain was reported in four trials each comparing different types of interventions.

Clapp 2002a looked at whether an intervention encouraging different exercise intensities at different stages of pregnancy (before versus after 20 weeks gestation) had an impact on pregnancy weight gain. Results suggest that low intensity exercise in early pregnancy moving on to higher intensity exercise after 20 weeks was associated with a lower pregnancy weight gain than either high followed by low intensity exercise or moderate exercise throughout (MD -3.50, 95% CI -5.86 to -1.14, and MD -2.60, 95% CI -4.96 to -0.24 respectively) (Analysis 2.1).

Moses 2006 examined low versus high glycaemic diets and found no clear differences in pregnancy weight gain between groups (MD 1.40, 95% CI -0.62 to 3.42). Dietary counselling with a probiotic supplement did not seem to be associated with any differences in weight gain compared with counselling alone (MD 0.20, 95% CI -1.21 to 1.61) (Laitinen 2009) (Analysis 2.1).

Clapp 2002 in a study with 20 women examined a low glycaemic diet plus exercise versus a high glycaemic diet plus exercise and reported a considerably lower mean weight gain in the low glycaemic group (MD -8.20, 95% CI -11.27 to -5.13).

One trial (Bechtel-Blackwell 2002) comparing computer-assisted self-interview plus nutrition education with computer-assisted self-interview plus standard nutritional counselling reported the data of weight gain in each trimester but did not report standard deviation; we have set out findings in an additional table (Table 3).

Table 3. Weight gain (computer-assisted self-interview plus nutrition education)
StudyTrimesterCASI plus nutrition educationCASI plus standard nutrition counsellingFP value
nMean weight gain (lb.)nMean weight gain (lb.)6.130.0000
Bechtel-Blackwell 20021173.20186.276.130.0000
 22214.512414.882.330.056
 32215.142412.293.440.0060
2.2 Caesarean delivery

The number of women needing caesarean delivery was reported in a single trial comparing low and high glycaemic diets (Moses 2006). There was no significant difference between groups (RR 1.25, 95% CI 0.49 to 3.18) (Analysis 2.2).

2.3 - 2.4 Behaviour modification outcomes: diet, physical activity

In a three-arm trial Laitinen 2009 examined the effects of dietary counselling with or without probiotic supplements compared with controls; when the two intervention arms were compared there was no clear evidence that one intervention was superior to the other in terms of differences in reported mean energy or fibre intake compared with controls (Analysis 2.3; Analysis 2.4). Reported energy and fibre intake were also compared in the trial by Moses 2006 looking at high and low glycaemic diets; there was no clear evidence of differences between interventions for these outcomes (Analysis 2.3; Analysis 2.4). None of the studies reported results for activity rates for women receiving different types of interventions.

None of the included studies with general population samples reported findings for other maternal outcomes in this comparison.

For the newborns
2.5 - 2.6 High and low birthweight

None of the studies in this comparison reported on the number of babies with birthweight greater than 4000 gm. Moses 2006 comparing low and high glycaemic diets with 62 women found a lower number of babies with birthweight above the 90th centile for gestational age in the low glycaemic diet group (RR 0.09, 95% CI 0.01 to 0.69) (Analysis 2.5). This same study also reported babies with birthweight below the 10th centile and there were no apparent differences between groups (RR 1.41, 95% CI 0.25 to 7.84) (Analysis 2.6).

No studies in this comparison reported findings for other outcomes for newborns.

Long-term health outcomes
Maternal weight retention

Maternal weight retention in the postnatal period was not reported in these studies.

3. Interventions to prevent excessive weight gain versus standard care or routine care (interventions in high-risk groups) (10 trials)

Primary outcome
3.1 Excessive weight gain

This outcome was reported in four trials (Guelinckx 2010; Jeffries 2009; Phelan 2011; Polley 2002). The trial by Guelinckx 2010 had three arms. For women in high-risk groups, none of these interventions was associated with any difference in the number of women gaining excessive weight compared with controls receiving standard care (behavioural counselling, RR 1.19 95% CI 0.96 to 1.47 (Phelan 2011; Polley 2002); regular weight measurement, RR 0.92, 95% CI 0.53 to 1.62 (Jeffries 2009); or nutritional advice from a brochure with or without behavioural counselling, (RR 0.83, 95% CI 0.51 to 1.34, and RR 0.94, 95% CI 0.59 to 1.50 respectively (Guelinckx 2010)) (Analysis 3.1).

Secondary outcomes
For the mothers
3.2 Weight gain

Weight gain was reported in nine trials (one with two intervention arms Guelinckx 2010). Seven different interventions were examined and overall, only one intervention type (involving regular weight monitoring, counselling and continuity of caregivers) was associated with a statistically significant lower mean weight gain in the intervention group: Quinlivan 2011 in a study involving 124 women reported women in the intervention arm gaining on average 6.8 kg less than controls (95% CI -8.63 to -4.87).

Two studies (Rae 2000; Wolff 2008) examined energy restriction counselling. (Rae 2000 recruited women at high risk of gestational diabetes and Wolff 2008 women who were overweight or obese at the start of pregnancy). In the study recruiting women with a high BMI (Wolff 2008), weight gain was 6.7 kg less in the intervention group (95% CI -10.31 to -3.09); this difference between groups was statistically significant. In the study by Rae 2000 examining a similar intervention, there was no strong evidence of any difference between groups (MD 1.88, 95% CI -1.96 to 5.72).

For other types of interventions there were no significant differences between groups in mean weight gain for women in high-risk groups (behavioural counselling (two studies, MD 0.60, 95% CI -1.30 to 2.51), regular weight measurement (one study, MD -0.08, 95% CI -2.00 to 1.84), diet and exercise counselling (two studies, MD -1.15, 95% CI -2.93 to 0.63) and a nutrition brochure with or without counselling, MD -0.80, 95% CI -3.89 to 2.29 and MD 0.30, 95% CI -2.44 to 3.04 respectively) (Analysis 3.2).

3.3 Low weight gain

This outcome was reported in two trials with 226 high-risk women examining a behavioural counselling intervention; there was no significant difference between groups (MD 0.80, 95% CI 0.44 to 1.47) (Analysis 3.3).

3.4 Preterm birth

Three trials examining two different interventions (regular weight monitoring and continuity of care (Quinlivan 2011) and behavioural counselling (Phelan 2011; Polley 2002)) reported findings for preterm birth. There were no significant differences in the number of preterm births in the intervention and control groups for either intervention (RR 0.97, 95% CI 0.06 to 15.14, and RR 1.20, 95% CI 0.54 to 2.64 respectively) (Analysis 3.4).

3.5 Pre-eclampsia

This outcome was measured in six trials examining five different interventions. None of these interventions was associated with significant differences between groups for pre-eclampsia (behavioural counselling, RR 1.38, 95% CI 0.73 to 2.60 (Phelan 2011; Polley 2002); diet and exercise counselling, RR 1.24, 95% CI 0.22 to 7.05 (Luoto 2011 cluster-randomised trial); brochure with or without diet counselling, RR 0.51, 95% CI 0.05 to 5.44 and RR 0.39, 95% CI 0.02 to 9.20 respectively (Guelinckx 2010); and energy restriction counselling for women with a high BMI RR 0.39 95% CI 0.02 to 9.11, or women at high risk of gestation diabetes RR 0.92, 95% CI 0.48 to 1.79 (Rae 2000; Wolff 2008) (Analysis 3.5).

3.6 - 3.7 Need for and indication for induction of labour and caesarean delivery

Two included studies with high-risk samples reported on the number of women requiring induction of labour (Guelinckx 2010; Rae 2000); there was no clear evidence of differences between controls and groups receiving energy restriction counselling (RR 1.08, 95% CI 0.72 to 1.63) or a nutrition brochure with or without counselling (RR 0.90, 95% CI 0.60 to 1.34, and RR 0.83, 95% CI 0.51 to 1.36 respectively) (Analysis 3.6). The number of women experiencing caesarean delivery was reported in five trials. There were no clear differences between groups receiving interventions involving behaviour counselling (two trials, RR 0.76, 95% CI 0.54 to 1.05); a nutrition brochure with or without counselling (one trial, RR 0.65, 95% CI 0.28 to 1.52, and RR 1.49, 95% CI 0.62 to 3.62 respectively); or energy restriction counselling (two trials,(high BMI, RR 0.78, 95% CI 0.14 to 4.29; high risk of gestational diabetes RR 1.17, 95% CI 0.74 to 1.87) compared with controls (Analysis 3.7).

3.8 - 3.11 Behaviour modification outcomes: diet, physical activity

Three trials examined mean reported energy intake. Guelinckx 2010 reported lower energy intake for women receiving a nutrition brochure with or without counselling compared with controls (MD -1586.80(kj), 95% CI -2417.92 to -755.68 and MD -1678.90 (kj), 95% CI -2381.74 to -976.06 respectively). The results from two studies (Rae 2000; Wolff 2008) examining energy restriction counselling in high-risk groups showed that energy intake (kj) was significantly reduced in the intervention group in a study recruiting women with high BMI (MD -2057.00, 95% CI -3261.43 to - 852.57) whereas in a study recruiting women at high risk of gestational diabetes there was a relatively small, and statistically non significant reduction in intake (MD -266.00 kg, 95% CI -733.09 to 201.09) (Analysis 3.8).

Guelinckx 2010 also reported results for fibre intake. There was no apparent difference between groups (Analysis 3.9). Physical activity scores were also examined in this study and women receiving nutrition brochures with or without counselling had similar mean scores compared with controls (Analysis 3.10).

Finally, a study examining an exercise intervention found no significant evidence of a difference between groups in the number of women engaging in physical activity equivalent to > 900 kcal energy expenditure per week (RR 1.73, 95% CI 0.96 to 3.10) (Callaway 2010, Analysis 3.11).

For the newborns
3.12 - 3.15 High and low birthweight

Six studies (examining five different interventions) reported the number of babies with a birthweight above 4000 gm. None of the interventions showed evidence of a significant difference between groups (Analysis 3.12) (behavioural counselling RR 1.06, 95% CI 0.54 to 2.09; nutrition brochure RR 1.94, 95% CI 0.50 to 7.56; nutrition brochure plus counselling RR 0.61, 95% CI 0.16 to 2.41; energy restriction counselling RR 1.57, 95% CI 0.62 to 3.97; diet and exercise counselling RR 0.93, 95% CI 0.39 to 2.19). Two additional studies examining energy restriction counselling (Rae 2000) and a cluster-randomised trial (Luoto 2011) looking at a diet and exercise counselling reported on the number of babies with birthweight above the 90th centile. Again, there was no clear difference between intervention and control groups (RR 1.19, 95% CI 0.64 to 2.19 and RR 0.62, 95% CI 0.23 to 1.64 respectively) (Analysis 3.13).

Three studies reported on the number of babies with low birthweight. There was no strong evidence that interventions were associated with low infant birthweight (behavioural counselling (two studies) RR 0.99, 95% CI 0.34 to 2.95; diet and exercise counselling RR 1.65, 95% CI 0.15 to 17.54) (Analysis 3.14; Analysis 3.15).

3.16 - 3.17 Complication related to macrosomia

A single study examining weight restriction counselling reported the number of babies with neonatal hypoglycaemia and with shoulder dystocia at the birth (Rae 2000); there was no clear difference between groups for either outcome (Analysis 3.16; Analysis 3.17).

Long-term health outcomes
3.18 - 3.19 Maternal weight retention

Two studies reported on mean maternal weight retention. A study with a sample of 39 women (Polley 2002) looking at behavioural counselling and a study by Wolff 2008 examining energy restriction counselling reported on the mean weight retention in the postpartum period. Neither study demonstrated significant differences in mean weight retention between intervention and control groups (Analysis 3.18).

A single study with results for 177 high-risk women examining behavioural counselling interventions (Phelan 2011) found no differences between intervention and control women in terms of the number of women above their prepregnancy or early pregnancy weight at six months postpartum (RR 0.90, 95% CI 0.77 to 1.05) (Analysis 3.19).

4. Interventions to prevent excessive weight gain: alternative interventions (interventions in high risk-groups) (five trials)

Primary outcome
4.1 Excessive weight gain

This outcome was reported in one trial (Guelinckx 2010) examining nutritional advice from a brochure with or without counselling, There was no significant difference between the two interventions for the number of women gaining excessive weight (RR 0.88, 95% CI 0.53 to 1.46) (Analysis 4.1).

Secondary outcomes
For the mothers
4.2 Weight gain

Weight gain was reported in four trials examining alternative interventions in high-risk groups. Only one trial with 232 women (Thornton 2009) examining nutritional counselling with or without nutritional monitoring found a significant difference between groups; the group that had the additional monitoring intervention had a lower mean weight gain (MD -9.07, 95% CI -10.90 to -7.24). For other types of interventions, it was not clear which type of intervention was associated with lower weight gain (low glycaemic load versus low fat diets (MD -0.50, 95% CI -3.29 to 2.29, Rhodes 2010), behavioural counselling with or without a nutritional brochure (MD -1.10, 95% CI -4.30 to 2.10, Guelinckx 2010), aerobic exercise with or without relaxation (RR -0.60, 95% CI -4.38 to 3.18 Santos 2005) (Analysis 4.2).

Low weight gain

No trials in this comparison reported on this outcome.

4.3 Preterm birth

Three trials examining different interventions reported on this outcome. It was not clear that any intervention was superior to alternatives in the number of preterm births (aerobic exercise with or without relaxation RR 1.89, 95% CI 0.18 to 19.95; nutrition counselling with or without monitoring RR 0.60, 95% CI 0.15 to 2.45; low GI versus low fat diet RR 3.50, 95% CI 0.42 to 28.91) (Analysis 4.3).

4.4 Pre-eclampsia

This outcome was measured in two trials examining different interventions. Neither trial showed evidence of a difference between two interventions (nutrition counselling with or without monitoring RR 0.64, 95% CI 0.26 to 1.58; nutrition brochure with or without counselling RR 4.42, 95% CI 0.22 to 89.18) (Analysis 4.4).

4.5 - 4.6 Need for and indication for induction of labour and caesarean delivery

Two included studies with high-risk samples reported on the number of women requiring induction of labour (Guelinckx 2010; Thornton 2009); there was no clear evidence of differences between groups (Analysis 4.5). The number of women experiencing caesarean delivery was reported in three trials (Guelinckx 2010; Rhodes 2010; Thornton 2009). There were no clear differences between groups receiving different types of interventions (low GI versus low fat diet RR 0.58, 95% CI 0.25 to 1.37; nutrition brochure with or without counselling RR 1.08, 95% CI 0.50 to 2.31; nutrition counselling with or without monitoring RR 1.10, 95% CI 0.94 to 1.27) (Analysis 4.6).

4.7 Postpartum complication

Thornton 2009 reported on postpartum complication including haemorrhage and infection postpartum and found no evidence of differences between groups (Analysis 4.7).

4.8 - 4.10 Behaviour modification outcomes: diet, physical activity

There were no clear differences between alternative interventions for reported energy or fibre intake or physical activity scores for women in high-risk groups (Analysis 4.8; Analysis 4.9; Analysis 4.10).

For the newborns
4.11 - 4.13 High and low birthweight

Three studies looked at infant birthweight above 4000 gm; there was no evidence significant differences between any of the two interventions compared (nutrition brochure with or without counselling RR 0.88, 95% CI 0.28 to 2.80; nutritional counselling with or without monitoring RR 2.25, 95% CI 0.71 to 7.10; low GI versus low fat diet RR 1.75, 95% CI 0.17 to 17.95) (Analysis 4.11). Two additional studies reported on the number of babies with birthweight above the 90th centile. Again, there was no clear difference between alternative intervention groups: low versus high glycaemic diet RR 1.03, 95% CI 0.23 to 4.73; low glycaemic load diet versus low fat diet RR 0.58, 95% CI 0.11 to 3.16) (Analysis 4.12).

One study comparing high versus low glycaemic diet reported on the number of babies with birthweight below the 10th centile. There was no strong evidence that any particular intervention was associated with lower infant birthweight (RR 5.16, 95% CI 0.26 to 103.27) (Analysis 4.13).

Complication related to macrosomia

No trials in this comparison reported on this outcome.

Long-term health outcomes
4.14 Maternal weight retention

A single trial with 232 women reported on mean maternal weight retention in high-risk groups (Thornton 2009). This study suggested that the addition of nutritional monitoring to a counselling intervention led to considerably less weight retention (MD -13.71, 95% CI -14.48 to -12.94) (Analysis 4.14).

Appetite suppressant drugs versus placebo (two trials)

Two trials examined the effects of diethylpropion hydrochloride (appetite suppressant drug) versus placebo (Boileau 1968; Silverman 1971); the results from these trials were not reported in a way that allowed us to include them in the analysis. The results are set out in additional tables (Table 4). Both of these studies are now more than 40 years old and we are not aware that these drugs are now used in obstetric practice.

Table 4. Weight change during therapy (use of an appetite suppressant)
StudyDiethylpropion hydrochloridePlacebo
nDuration of therapy (weeks)Average weight change (lb.)nDuration of therapy (weeks)Average weight change (lb.)
Silverman 19712810.96.97910.98.78
Boileau 19685213.01.25312.97.0

Discussion

Summary of main results

Overall, results from this review were mainly not statistically significant, and where there did appear to be differences between intervention and control groups, results were not consistent. For many outcomes only one or two studies reported results. For many outcomes studies did not have sufficient statistical power to detect differences between groups.

For those trials recruiting pregnant women from general clinic populations (which may have included some overweight and obese women and women with other risk factors), findings were inconsistent. Only four trials (examining three different types of interventions) reported on the number of women gaining excessive weight during pregnancy; only one of the three intervention types (behavioural counselling) was associated with a positive treatment effect. Mean weight gain in pregnancy was reported for six different types of interventions; three (behavioural counselling, an intensive exercise intervention and a combined diet and exercise intervention) seemed to have positive effects. Two types of interventions (a single study of each intervention) were associated with women being less likely to retain weight in the postpartum period. For other outcomes (often reported in single studies), there was no clear evidence of differences between groups (low maternal weight gain, preterm birth, pre-eclampsia, caesarean section, high and low infant birthweight and birth and infant complications). There was some evidence from single studies that interventions may have a positive effect on reported behaviour (e.g. activity scores); although without blinding such results are difficult to interpret.

Where two or more alternative interventions were compared in women recruited from general clinic populations results were from single studies. The finding indicated that a low glycaemic diet with exercise was more effective in reducing pregnancy weight gain than a high glycaemic diet with exercise. A study examining different patterns of exercise during pregnancy reported that low intensity exercise in early pregnancy followed by high intensity exercise later in pregnancy was associated with lower weight gain than other patterns of exercise. For the newborn outcomes, a single study reported that a low glycaemic diet was associated with a lower number of babies with birthweight above the 90th centile for gestational age than a high glycaemic diet. However, overall there was very little evidence about the relative effects of alternative types of interventions on most of the review outcomes; outcomes were either not reported or differences between groups were not statistically significant.

For studies recruiting women or reporting results for women in high-risk groups (recruiting only women that were overweight or obese or with other risk factors), results were also inconsistent and for most outcomes interventions were not associated with statistically significant positive effects. Four trials reported on excessive weight gain but no intervention was associated with a statistically significant reduction in the number of women gaining excessive weight. One of seven different interventions was associated with a reduction in mean weight gain (this intervention involved weight monitoring, continuity of care and counselling), for the remaining six interventions there were no significant differences between groups. For reported behaviour change there was some evidence that women in intervention groups reported lower energy intake. For other outcomes there was no strong evidence of differences between control and intervention groups. Where alternative interventions were compared, only one trial reported on excessive weight gain with no positive effect. A significant effect on lower mean weight gain was found only in one (addition of nutrition monitoring to a counselling intervention) of four alternative comparisons; this intervention was also associated with women being less likely to retain weight in the postpartum period.There was no clear evidence that one type of intervention was better than another for other outcomes.

Overall completeness and applicability of evidence

Almost all of the included studies were carried out in developed countries and it is not clear that the results are applicable in other contexts. The transfer of an intervention from one setting to another may reduce its effectiveness. There was considerable variation in the nature of interventions as well as in outcomes reported among studies. Therefore, although we have included data from 27 studies in the review, there were limited data for most types of interventions and outcomes were measured in different ways, so only few of the results could be combined, especially for the main outcome of interest. The overall completeness of evidence in this review is therefore too limited to allow us to reach any strong conclusions or to generalise.

Quality of the evidence

We included 28 studies with 27 studies involving 3964 women contributing data to the analyses. Seventeen out of 27 included studies contributing data were assessed as being at low risk of bias for generation of the randomisation sequence and twelve used methods that we judged were at low risk of bias for allocation concealment (see Figure 1). Achieving blinding for most interventions would be difficult, and lack of blinding may have had an impact on some outcomes (e.g. self-report of activity levels and other behavioural outcomes).

Potential biases in the review process

We took a number of steps to minimise bias in the review process. We strictly followed the process recommended by the Cochrane Pregnancy and Childbirth Review Group. We were able to obtain all relevant studies identified from search results. We independently reviewed all potentially relevant studies and resolved disagreement by discussion.

Agreements and disagreements with other studies or reviews

Two recent systematic reviews (Ronnberg 2010; Skouteris 2010), which identified the effects of interventions to reduce excessive weight gain during pregnancy, concluded similar results to our review: that none of the trials showed any significant difference in proportion of excessive weight gain, and that there was inconsistency in the results to reduce gestational weight gain between the treatment and control groups. However, these two reviews included only studies comparing interventions with standard maternity care, and included not only RCTs, but also non-RCTs.

We identified two other systematic reviews of RCTs. The review by Kuhlmann 2008 assessed weight-management interventions for pregnant or postpartum women. Only one study conducted among pregnant women was included in this review. The other RCT review, by Dodd 2008 (updated by Dodd 2010b), identified the risks and benefits of dietary and lifestyle interventions to limit weight gain during pregnancy in overweight and obese women. The reviews reported similar results to our review: that there were no statistically significant differences identified between the intervention and standard care groups for maternal or infant health outcomes.

One Cochrane review showed that energy or protein restriction advice for overweight pregnant women significantly reduced weekly maternal weight gain (Kramer 2003), but our review found that there was no significant difference in mean weight gain between energy restriction counselling and standard care.

Authors' conclusions

Implications for practice

The results of the review were inconsistent. Some interventions for general population groups had promising results but none of the interventions were effective in preventing excessive weight gain in high-risk groups. Similarly, for the mean weight gain outcome, some diet and or exercise interventions appeared to be effective compared with routine care although only one of seven different interventions achieved positive effect in high-risk groups. Interventions did not seem to have any positive (or negative) effect on other maternal and infant outcomes. However, most results were from only one or two studies and there is not enough evidence to recommend any particular intervention for preventing excessive weight gain during pregnancy. In addition, methodological limitations among the included studies and the observed effect sizes were generally small, therefore, caution is needed in applying these results.

Implications for research

There is a need to conduct high quality RCTs with adequate sample sizes to evaluate the effectiveness of potential interventions for preventing excessive weight gain during pregnancy. In addition, not only should total weight gain be measured, but also the proportion of women who have weight gain above and below the recommendations. In addition, it would be interesting to examine women's compliance in programmes to restrict weight gain. Furthermore, the effectiveness of interventions for women with non-Western lifestyles should also be assessed.

Acknowledgements

We would like to acknowledge the staff of Cochrane Pregnancy and Childbirth Group for assistance with searching references and providing technical guidance.

As part of the prepublication editorial process, this review has been commented on by three peers (an editor and two referees who are external to the editorial team) and the Group's Statistical Adviser.

Data and analyses

Download statistical data

Comparison 1. Interventions to prevent excessive weight gain versus standard care or routine care (general population)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Excessive weight gain4 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
1.1 Behavioural counselling versus standard care2247Risk Ratio (M-H, Fixed, 95% CI)0.72 [0.54, 0.95]
1.2 Regular weight measurement versus standard care1152Risk Ratio (M-H, Fixed, 95% CI)0.57 [0.23, 1.40]
1.3 Exercise intervention plus dietary intervention versus standard care145Risk Ratio (M-H, Fixed, 95% CI)0.63 [0.23, 1.68]
2 Weight gain (kg)8 Mean Difference (IV, Fixed, 95% CI)Subtotals only
2.1 Behavioural counselling versus standard care3341Mean Difference (IV, Fixed, 95% CI)-1.39 [-2.48, -0.30]
2.2 Regular weight measurement versus standard care1152Mean Difference (IV, Fixed, 95% CI)-0.75 [-1.98, 0.48]
2.3 Regular supervised exercise versus routine care167Mean Difference (IV, Fixed, 95% CI)-2.0 [-3.26, -0.74]
2.4 Dietary counselling versus standard care (placebo)1171Mean Difference (IV, Fixed, 95% CI)0.0 [-1.53, 1.53]
2.5 Exercise intervention plus dietary intervention versus standard care2170Mean Difference (IV, Fixed, 95% CI)-2.03 [-2.99, -1.07]
2.6 Dietary counselling plus probiotics versus standard care (placebo)1170Mean Difference (IV, Fixed, 95% CI)0.20 [-1.22, 1.62]
3 Low weight gain2 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
3.1 Behavioural counselling versus standard care2247Risk Ratio (M-H, Fixed, 95% CI)1.33 [0.74, 2.37]
4 Preterm birth3 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
4.1 Regular weight measurement versus standard care1235Risk Ratio (M-H, Fixed, 95% CI)0.67 [0.15, 2.93]
4.2 Behavioural counselling versus standard care2243Risk Ratio (M-H, Fixed, 95% CI)0.75 [0.36, 1.58]
5 Pre-eclampsia3 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
5.1 Behavioural counselling versus standard care2243Risk Ratio (M-H, Fixed, 95% CI)0.34 [0.10, 1.22]
5.2 Regular weight measurement versus standard care1235Risk Ratio (M-H, Fixed, 95% CI)2.69 [0.55, 13.03]
6 Caesarean delivery5 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
6.1 Behavioural counselling versus standard care3343Risk Ratio (M-H, Fixed, 95% CI)0.78 [0.53, 1.16]
6.2 Regular weight measurement versus standard care1235Risk Ratio (M-H, Fixed, 95% CI)1.22 [0.82, 1.82]
6.3 Regular supervised exercise versus routine care167Risk Ratio (M-H, Fixed, 95% CI)0.68 [0.29, 1.57]
7 Energy intake (kj)1 Mean Difference (IV, Fixed, 95% CI)Subtotals only
7.1 Dietary counselling versus standard care (placebo)1135Mean Difference (IV, Fixed, 95% CI)-170.00 [-694.76, 350.76]
7.2 Dietary counselling plus probiotics versus standard care (placebo)1132Mean Difference (IV, Fixed, 95% CI)104.0 [-421.32, 629.32]
8 Fibre intake (gm)1 Mean Difference (IV, Fixed, 95% CI)Subtotals only
8.1 Dietary counselling versus standard care (placebo)1135Mean Difference (IV, Fixed, 95% CI)1.10 [-0.91, 3.11]
8.2 Dietary counselling plus probiotics versus standard care (placebo)1132Mean Difference (IV, Fixed, 95% CI)1.70 [-0.32, 3.72]
9 Physical activity score2 Mean Difference (IV, Fixed, 95% CI)Subtotals only
9.1 Exercise intervention plus dietary intervention versus standard care2170Mean Difference (IV, Fixed, 95% CI)0.63 [0.35, 0.91]
10 Physical activity (reporting 30 min exercise on most days)1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
10.1 Interactive diet and exercise video counselling versus routine care1287Risk Ratio (M-H, Fixed, 95% CI)1.31 [0.92, 1.86]
11 Infant birthweight > 4000 gm4 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
11.1 Behavioural counselling versus standard care2243Risk Ratio (M-H, Fixed, 95% CI)2.19 [0.63, 7.60]
11.2 Regular supervised exercise versus routine care167Risk Ratio (M-H, Fixed, 95% CI)0.65 [0.12, 3.63]
11.3 Exercise intervention plus dietary intervention versus standard care145Risk Ratio (M-H, Fixed, 95% CI)0.44 [0.09, 2.15]
12 Infant birthweight > 90th centile1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
12.1 Regular weight measurement versus standard care1235Risk Ratio (M-H, Fixed, 95% CI)0.65 [0.27, 1.56]
13 Infant birthweight < 2500 gm2 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
13.1 Behavioral counselling versus standard care2243Risk Ratio (M-H, Fixed, 95% CI)1.03 [0.40, 2.63]
14 Infant birthweight < 10th centile1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
14.1 Regular weight measurement versus standard care1235Risk Ratio (M-H, Fixed, 95% CI)0.67 [0.29, 1.53]
15 Neonatal hypoglycaemia1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
15.1 Regular weight measurement versus standard care1235Risk Ratio (M-H, Fixed, 95% CI)2.69 [0.28, 25.44]
16 Shoulder dystocia1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
16.1 Regular weight measurement versus standard care1235Risk Ratio (M-H, Fixed, 95% CI)0.90 [0.06, 14.14]
17 Maternal weight retention (kg)1 Mean Difference (IV, Fixed, 95% CI)Subtotals only
17.1 Behavioural counselling versus standard care139Mean Difference (IV, Fixed, 95% CI)-1.80 [-4.95, 1.35]
18 Maternal weight gain above prepregnancy weight at 6 months postpartum2 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
18.1 Behavioural counselling versus standard care1186Risk Ratio (M-H, Fixed, 95% CI)0.80 [0.67, 0.97]
18.2 Exercise intervention plus dietary intervention versus standard care1125Risk Ratio (M-H, Fixed, 95% CI)0.35 [0.19, 0.63]
Analysis 1.1.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 1 Excessive weight gain.

Analysis 1.2.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 2 Weight gain (kg).

Analysis 1.3.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 3 Low weight gain.

Analysis 1.4.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 4 Preterm birth.

Analysis 1.5.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 5 Pre-eclampsia.

Analysis 1.6.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 6 Caesarean delivery.

Analysis 1.7.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 7 Energy intake (kj).

Analysis 1.8.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 8 Fibre intake (gm).

Analysis 1.9.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 9 Physical activity score.

Analysis 1.10.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 10 Physical activity (reporting 30 min exercise on most days).

Analysis 1.11.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 11 Infant birthweight > 4000 gm.

Analysis 1.12.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 12 Infant birthweight > 90th centile.

Analysis 1.13.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 13 Infant birthweight < 2500 gm.

Analysis 1.14.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 14 Infant birthweight < 10th centile.

Analysis 1.15.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 15 Neonatal hypoglycaemia.

Analysis 1.16.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 16 Shoulder dystocia.

Analysis 1.17.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 17 Maternal weight retention (kg).

Analysis 1.18.

Comparison 1 Interventions to prevent excessive weight gain versus standard care or routine care (general population), Outcome 18 Maternal weight gain above prepregnancy weight at 6 months postpartum.

Comparison 2. Interventions to prevent excessive weight gain versus other interventions (general population)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Weight gain (kg)4 Mean Difference (IV, Fixed, 95% CI)Subtotals only
1.1 Low-high exercise versus moderate-moderate exercise150Mean Difference (IV, Fixed, 95% CI)-2.60 [-4.96, -0.24]
1.2 Low-high exercise versus high-low exercise151Mean Difference (IV, Fixed, 95% CI)-3.50 [-5.86, -1.14]
1.3 High-low exercise versus moderate-moderate exercise149Mean Difference (IV, Fixed, 95% CI)0.90 [-1.59, 3.39]
1.4 Low glycaemic diet versus high glycaemic diet162Mean Difference (IV, Fixed, 95% CI)1.40 [-0.62, 3.42]
1.5 Dietary counselling plus probiotic versus dietary counselling1171Mean Difference (IV, Fixed, 95% CI)0.20 [-1.21, 1.61]
1.6 Low glycaemic diet plus exercise versus high glycaemic diet plus exercise120Mean Difference (IV, Fixed, 95% CI)-8.20 [-11.27, -5.13]
2 Caesarean delivery1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
2.1 Low glycaemic diet versus high glycaemic diet162Risk Ratio (M-H, Fixed, 95% CI)1.25 [0.49, 3.18]
3 Energy intake (kj)2 Mean Difference (IV, Fixed, 95% CI)Subtotals only
3.1 Low glycaemic diet versus high glycaemic diet160Mean Difference (IV, Fixed, 95% CI)-280.0 [-1225.93, 665.93]
3.2 Dietary counselling plus probiotic versus dietary counselling1139Mean Difference (IV, Fixed, 95% CI)276.0 [-243.57, 795.57]
4 Fibre intake (gm)2 Mean Difference (IV, Fixed, 95% CI)Subtotals only
4.1 Low glycaemic diet versus high glycaemic diet160Mean Difference (IV, Fixed, 95% CI)-0.60 [-4.25, 3.05]
4.2 Dietary counselling plus probiotic versus dietary counselling1139Mean Difference (IV, Fixed, 95% CI)0.60 [-1.35, 2.55]
5 Infant birthweight > 90th centile for gestational age1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
5.1 Low glycaemic diet versus high glycaemic diet162Risk Ratio (M-H, Fixed, 95% CI)0.09 [0.01, 0.69]
6 Infant birthweight <10th centile for gestational age1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
6.1 Low glycaemic diet versus high glycaemic diet162Risk Ratio (M-H, Fixed, 95% CI)1.41 [0.25, 7.84]
Analysis 2.1.

Comparison 2 Interventions to prevent excessive weight gain versus other interventions (general population), Outcome 1 Weight gain (kg).

Analysis 2.2.

Comparison 2 Interventions to prevent excessive weight gain versus other interventions (general population), Outcome 2 Caesarean delivery.

Analysis 2.3.

Comparison 2 Interventions to prevent excessive weight gain versus other interventions (general population), Outcome 3 Energy intake (kj).

Analysis 2.4.

Comparison 2 Interventions to prevent excessive weight gain versus other interventions (general population), Outcome 4 Fibre intake (gm).

Analysis 2.5.

Comparison 2 Interventions to prevent excessive weight gain versus other interventions (general population), Outcome 5 Infant birthweight > 90th centile for gestational age.

Analysis 2.6.

Comparison 2 Interventions to prevent excessive weight gain versus other interventions (general population), Outcome 6 Infant birthweight <10th centile for gestational age.

Comparison 3. Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Excessive weight gain4 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
1.1 Behavioural counselling versus standard care2226Risk Ratio (M-H, Fixed, 95% CI)1.19 [0.96, 1.47]
1.2 Regular weight measurement versus standard care184Risk Ratio (M-H, Fixed, 95% CI)0.92 [0.53, 1.62]
1.3 Nutritional advice from brochure versus standard care180Risk Ratio (M-H, Fixed, 95% CI)0.94 [0.59, 1.50]
1.4 Behavioural counselling plus nutritional advice from a brochure versus standard care185Risk Ratio (M-H, Fixed, 95% CI)0.83 [0.51, 1.34]
2 Weight gain (kg)9 Mean Difference (IV, Fixed, 95% CI)Subtotals only
2.1 Behavioural counselling versus standard care2212Mean Difference (IV, Fixed, 95% CI)0.60 [-1.30, 2.51]
2.2 Regular weight measurement versus standard care176Mean Difference (IV, Fixed, 95% CI)-0.08 [-2.00, 1.84]
2.3 Nutritional advice from a brochure versus standard care180Mean Difference (IV, Fixed, 95% CI)0.30 [-2.44, 3.04]
2.4 Energy restriction counselling versus standard care (High BMI)150Mean Difference (IV, Fixed, 95% CI)-6.70 [-10.31, -3.09]
2.5 Energy restriction counselling versus standard care (high risk gestational diabetes)1117Mean Difference (IV, Fixed, 95% CI)1.88 [-1.96, 5.72]
2.6 Weight monitoring, continuity of care and counselling versus routine1124Mean Difference (IV, Fixed, 95% CI)-6.80 [-8.63, -4.97]
2.7 Diet and exercise counselling versus standard care2147Mean Difference (IV, Fixed, 95% CI)-1.15 [-2.93, 0.63]
2.8 Behavioural counselling plus nutritional advice from a brochure versus standard care185Mean Difference (IV, Fixed, 95% CI)-0.80 [-3.89, 2.29]
3 Low weight gain2 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
3.1 Behavioural counselling versus standard care2226Risk Ratio (M-H, Fixed, 95% CI)0.80 [0.44, 1.47]
4 Preterm birth3 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
4.1 Weight monitoring, continuity of care and counselling versus routine1124Risk Ratio (M-H, Fixed, 95% CI)0.97 [0.06, 15.14]
4.2 Behavioural counselling versus standard care2216Risk Ratio (M-H, Fixed, 95% CI)1.20 [0.54, 2.64]
5 Pre-eclampsia6 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
5.1 Behavioural counselling versus standard care2216Risk Ratio (M-H, Fixed, 95% CI)1.38 [0.73, 2.60]
5.2 Diet and exercise counselling versus standard care193Risk Ratio (M-H, Fixed, 95% CI)1.24 [0.22, 7.05]
5.3 Nutritional advice from a brochure versus standard care180Risk Ratio (M-H, Fixed, 95% CI)0.39 [0.02, 9.20]
5.4 Energy restriction counselling versus standard care (High BMI)150Risk Ratio (M-H, Fixed, 95% CI)0.39 [0.02, 9.11]
5.5 Energy restriction counselling versus standard care (high risk gestational diabetes)1117Risk Ratio (M-H, Fixed, 95% CI)0.92 [0.48, 1.79]
5.6 Behavioural counselling plus nutritional advice from a brochure versus standard care185Risk Ratio (M-H, Fixed, 95% CI)0.51 [0.05, 5.44]
6 Induction of labour2 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
6.1 Nutritional advice from a brochure versus standard care180Risk Ratio (M-H, Fixed, 95% CI)0.83 [0.51, 1.36]
6.2 Energy restriction counselling versus standard care1117Risk Ratio (M-H, Fixed, 95% CI)1.08 [0.72, 1.63]
6.3 Behavioural counselling plus nutritional advice from a brochure versus standard care185Risk Ratio (M-H, Fixed, 95% CI)0.90 [0.60, 1.34]
7 Caesarean delivery5 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
7.1 Behavioural counselling versus standard care2216Risk Ratio (M-H, Fixed, 95% CI)0.76 [0.54, 1.05]
7.2 Nutritional advice from a brochure versus standard care180Risk Ratio (M-H, Fixed, 95% CI)1.49 [0.62, 3.62]
7.3 Energy restriction counselling versus standard care (High BMI)150Risk Ratio (M-H, Fixed, 95% CI)0.78 [0.14, 4.29]
7.4 Energy restriction counselling versus standard care (high risk gestational diabetes)1117Risk Ratio (M-H, Fixed, 95% CI)1.17 [0.74, 1.87]
7.5 Behavioural counselling plus nutritional advice from a brochure versus standard care185Risk Ratio (M-H, Fixed, 95% CI)0.65 [0.28, 1.52]
8 Energy intake (kj)3 Mean Difference (IV, Fixed, 95% CI)Subtotals only
8.1 Nutritional advice from a brochure versus standard care180Mean Difference (IV, Fixed, 95% CI)-1678.90 [-2381.74, -976.06]
8.2 Energy restriction counselling versus standard care (high BMI)143Mean Difference (IV, Fixed, 95% CI)-2057.0 [-3261.43, -852.57]
8.3 Energy restriction counselling versus standard care (high risk gestational diabetes)1117Mean Difference (IV, Fixed, 95% CI)-266.0 [-733.09, 201.09]
8.4 Behavioural counselling plus nutritional advice from a brochure versus standard care185Mean Difference (IV, Fixed, 95% CI)-1586.80 [-2417.92, -755.68]
9 Fibre intake (gm)1 Mean Difference (IV, Fixed, 95% CI)Subtotals only
9.1 Nutritional advice from a brochure versus standard care180Mean Difference (IV, Fixed, 95% CI)2.0 [-0.64, 4.64]
10 Physical activity score1 Mean Difference (IV, Fixed, 95% CI)Subtotals only
10.1 Nutritional advice from a brochure versus standard care180Mean Difference (IV, Fixed, 95% CI)0.32 [-0.11, 0.75]
10.2 Behavioural counselling plus nutritional advice from a brochure versus standard care185Mean Difference (IV, Fixed, 95% CI)0.34 [-0.19, 0.87]
11 Physical activity (> 900 kcal/week expenditure) at 28 weeks1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
11.1 Exercise intervention versus standard care141Risk Ratio (M-H, Fixed, 95% CI)1.73 [0.96, 3.10]
12 Infant birthweight > 4000 gm5 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
12.1 Behavioural counselling versus standard care2216Risk Ratio (M-H, Fixed, 95% CI)1.06 [0.54, 2.09]
12.2 Nutritional advice from a brochure versus standard care180Risk Ratio (M-H, Fixed, 95% CI)1.94 [0.50, 7.56]
12.3 Energy restriction counselling versus standard care1117Risk Ratio (M-H, Fixed, 95% CI)1.57 [0.62, 3.97]
12.4 Diet and exercise counselling versus standard care193Risk Ratio (M-H, Fixed, 95% CI)0.93 [0.39, 2.19]
12.5 Behavioural counselling plus nutritional advice from a brochure versus standard care185Risk Ratio (M-H, Fixed, 95% CI)0.61 [0.16, 2.41]
13 Infant birthweight > 90th centile2 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
13.1 Energy restriction counselling versus standard care1117Risk Ratio (M-H, Fixed, 95% CI)1.19 [0.64, 2.19]
13.2 Diet and exercise counselling versus standard care193Risk Ratio (M-H, Fixed, 95% CI)0.62 [0.23, 1.64]
14 Infant birthweight < 2500 gm2 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
14.1 Behavioural counselling versus standard care2216Risk Ratio (M-H, Fixed, 95% CI)0.99 [0.34, 2.95]
15 Infant birthweight < 10th centile1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
15.1 Diet and exercise counselling versus standard care193Risk Ratio (M-H, Fixed, 95% CI)1.65 [0.15, 17.54]
16 Neonatal hypoglycaemia1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
16.1 Energy restriction counselling versus standard care1110Risk Ratio (M-H, Fixed, 95% CI)0.73 [0.48, 1.13]
17 Shoulder dystocia1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
17.1 Energy restriction counselling versus standard care1117Risk Ratio (M-H, Fixed, 95% CI)0.12 [0.01, 2.33]
18 Maternal weight retention (kg)2 Mean Difference (IV, Fixed, 95% CI)Subtotals only
18.1 Behavioural counselling versus standard care135Mean Difference (IV, Fixed, 95% CI)3.30 [-0.88, 7.48]
18.2 Energy restriction counselling versus standard care135Mean Difference (IV, Fixed, 95% CI)-6.9 [-15.28, 1.48]
19 Maternal weight gain above prepregnancy weight at 6 months postpartum1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
19.1 Behavioural counselling versus standard care1177Risk Ratio (M-H, Fixed, 95% CI)0.90 [0.77, 1.05]
Analysis 3.1.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 1 Excessive weight gain.

Analysis 3.2.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 2 Weight gain (kg).

Analysis 3.3.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 3 Low weight gain.

Analysis 3.4.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 4 Preterm birth.

Analysis 3.5.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 5 Pre-eclampsia.

Analysis 3.6.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 6 Induction of labour.

Analysis 3.7.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 7 Caesarean delivery.

Analysis 3.8.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 8 Energy intake (kj).

Analysis 3.9.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 9 Fibre intake (gm).

Analysis 3.10.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 10 Physical activity score.

Analysis 3.11.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 11 Physical activity (> 900 kcal/week expenditure) at 28 weeks.

Analysis 3.12.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 12 Infant birthweight > 4000 gm.

Analysis 3.13.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 13 Infant birthweight > 90th centile.

Analysis 3.14.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 14 Infant birthweight < 2500 gm.

Analysis 3.15.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 15 Infant birthweight < 10th centile.

Analysis 3.16.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 16 Neonatal hypoglycaemia.

Analysis 3.17.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 17 Shoulder dystocia.

Analysis 3.18.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 18 Maternal weight retention (kg).

Analysis 3.19.

Comparison 3 Interventions to prevent excessive weight gain versus standard care or routine care (high-risk groups), Outcome 19 Maternal weight gain above prepregnancy weight at 6 months postpartum.

Comparison 4. Interventions to prevent excessive weight gain versus other interventions (high-risk groups)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Excessive weight gain1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
1.1 Behavioural counselling plus nutritional advice from a brochure versus nutritional advice from a brochure179Risk Ratio (M-H, Fixed, 95% CI)0.88 [0.53, 1.46]
2 Weight gain (kg)4 Mean Difference (IV, Fixed, 95% CI)Subtotals only
2.1 Low glycaemic load versus low fat diets138Mean Difference (IV, Fixed, 95% CI)-0.5 [-3.29, 2.29]
2.2 Behavioural counselling plus nutritional advice from a brochure versus nutritional advice from a brochure179Mean Difference (IV, Fixed, 95% CI)-1.10 [-4.30, 2.10]
2.3 Aerobic exercise plus relaxation versus relaxation172Mean Difference (IV, Fixed, 95% CI)-0.60 [-4.38, 3.18]
2.4 Nutritionally monitored plus nutritional counselling versus nutritional counselling1232Mean Difference (IV, Fixed, 95% CI)-9.07 [-10.90, -7.24]
3 Preterm birth3 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
3.1 Aerobic exercise plus relaxation versus relaxation172Risk Ratio (M-H, Fixed, 95% CI)1.89 [0.18, 19.95]
3.2 Nutritionally monitored plus nutritional counselling versus nutritional counselling1232Risk Ratio (M-H, Fixed, 95% CI)0.6 [0.15, 2.45]
3.3 Low glycaemic load versus low fat diets145Risk Ratio (M-H, Fixed, 95% CI)3.5 [0.42, 28.91]
4 Pre-eclampsia2 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
4.1 Behavioural counselling plus nutritional advice from a brochure versus nutritional advice from a brochure179Risk Ratio (M-H, Fixed, 95% CI)4.42 [0.22, 89.18]
4.2 Nutritionally monitored plus nutritional counselling versus nutritional counselling1232Risk Ratio (M-H, Fixed, 95% CI)0.64 [0.26, 1.58]
5 Induction of labour2 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
5.1 Behavioural counselling plus nutritional advice from a brochure versus nutritional advice from a brochure179Risk Ratio (M-H, Fixed, 95% CI)1.41 [0.88, 2.26]
5.2 Nutritionally monitored plus nutritional counselling versus nutritional counselling1232Risk Ratio (M-H, Fixed, 95% CI)0.71 [0.44, 1.15]
6 Caesarean delivery3 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
6.1 Low glycaemic load versus low fat diets145Risk Ratio (M-H, Fixed, 95% CI)0.58 [0.25, 1.37]
6.2 Behavioural counselling plus nutritional advice from a brochure versus nutritional advice from a brochure179Risk Ratio (M-H, Fixed, 95% CI)1.08 [0.50, 2.31]
6.3 Nutritionally monitored plus nutritional counselling versus nutritional counselling1232Risk Ratio (M-H, Fixed, 95% CI)1.10 [0.94, 1.27]
7 Haemorrhage/infection postpartum1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
7.1 Nutritionally monitored plus nutritional counselling versus nutritional counselling1232Risk Ratio (M-H, Fixed, 95% CI)0.73 [0.30, 1.74]
8 Energy intake (kj)2 Mean Difference (IV, Fixed, 95% CI)Subtotals only
8.1 Low glycaemic diet versus high glycaemic diet143Mean Difference (IV, Fixed, 95% CI)205.20 [-639.54, 1049.94]
8.2 Behavioural counselling plus nutritional advice from a brochure versus nutritional advice from a brochure179Mean Difference (IV, Fixed, 95% CI)92.10 [-644.14, 828.34]
9 Fibre intake (gm)1 Mean Difference (IV, Fixed, 95% CI)Subtotals only
9.1 Low glycaemic diet versus high glycaemic diet143Mean Difference (IV, Fixed, 95% CI)2.70 [-0.62, 6.02]
10 Physical activity score1 Mean Difference (IV, Fixed, 95% CI)Subtotals only
10.1 Behavioral counselling plus nutritional advice from a brochure versus nutritional advice from a brochure179Mean Difference (IV, Fixed, 95% CI)0.02 [-0.45, 0.49]
11 Infant birthweight > 4000 gm3 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
11.1 Behavioural counselling plus nutritional advice from a brochure versus nutritional advice from a brochure179Risk Ratio (M-H, Fixed, 95% CI)0.88 [0.28, 2.80]
11.2 Nutritionally monitored plus nutritional counselling versus nutritional counselling1232Risk Ratio (M-H, Fixed, 95% CI)2.25 [0.71, 7.10]
11.3 Low glycaemic load versus low fat diets145Risk Ratio (M-H, Fixed, 95% CI)1.75 [0.17, 17.95]
12 Infant birthweight > 90th centile for gestational age2 Risk Ratio (M-H, Random, 95% CI)Subtotals only
12.1 Low glycaemic diet versus high glycaemic diet163Risk Ratio (M-H, Random, 95% CI)1.03 [0.23, 4.73]
12.2 Low glycaemic load versus low fat diets145Risk Ratio (M-H, Random, 95% CI)0.58 [0.11, 3.16]
13 Infant birthweight < 10th centile for gestational age1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
13.1 Low glycaemic diet versus high glycaemic diet163Risk Ratio (M-H, Fixed, 95% CI)5.16 [0.26, 103.27]
14 Maternal weight retention (kg)1 Mean Difference (IV, Fixed, 95% CI)Subtotals only
14.1 Nutritionally monitored plus nutritional counselling versus nutritional counselling1232Mean Difference (IV, Fixed, 95% CI)-13.71 [-14.48, -12.94]
Analysis 4.1.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 1 Excessive weight gain.

Analysis 4.2.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 2 Weight gain (kg).

Analysis 4.3.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 3 Preterm birth.

Analysis 4.4.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 4 Pre-eclampsia.

Analysis 4.5.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 5 Induction of labour.

Analysis 4.6.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 6 Caesarean delivery.

Analysis 4.7.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 7 Haemorrhage/infection postpartum.

Analysis 4.8.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 8 Energy intake (kj).

Analysis 4.9.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 9 Fibre intake (gm).

Analysis 4.10.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 10 Physical activity score.

Analysis 4.11.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 11 Infant birthweight > 4000 gm.

Analysis 4.12.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 12 Infant birthweight > 90th centile for gestational age.

Analysis 4.13.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 13 Infant birthweight < 10th centile for gestational age.

Analysis 4.14.

Comparison 4 Interventions to prevent excessive weight gain versus other interventions (high-risk groups), Outcome 14 Maternal weight retention (kg).

Appendices

Appendix 1. MEDLINE search strategy

1 exp Pregnancy/
2 Pregnant Women/
3 1 or 2
4 Weight Gain/
5 exp Obesity/pc [Prevention & Control]
6 exp Clinical Trial/
7 randomized.ti,ab.
8 placebo.ti,ab.
9 dt.fs.
10 randomly.ti,ab.
11 trial.ti,ab.
12 groups.ti,ab.
13 or/6-12
14 Animals/
15 Humans/
16 14 not (14 and 15)
17 13 not 16
18 4 or 5
19 17 and 18 and 3

History

Protocol first published: Issue 2, 2008
Review first published: Issue 4, 2012

DateEventDescription
10 November 2008AmendedThe Types of interventions section has been amended by the inclusion of the phrase 'or other interventions for preventing excessive weight gain in pregnancy'. This amendment has been made to ensure that the selection criteria are consistent with the objectives of the review which are to evaluate the effectiveness of all interventions (or combinations of interventions) to prevent excessive weight gain.

Contributions of authors

B Muktabhant (BM) conceived and designed the draft protocol. P Lumbiganon (PL) and C Ngamjarus (CN) reviewed and commented on the revisions of the protocol. BM, CN and T Dowswell (TD) selected studies, extracted data and conducted data analysis. PL commented on data analysis through discussion. BM and TD drafted the review. PL and CN revised the drafted review and approved the final version of the review.

Declarations of interest

None known.

Sources of support

Internal sources

  • Khon Kaen University, Thailand.

  • University of Liverpool, UK.

External sources

  • Thai Cochrane Network, Thailand.

  • Thailand Research Fund (Senior Research Scholar), Thailand.

  • NIHR NHS, UK.

    TD is supported by the NIHR NHS Cochrane Collaboration Programme grant scheme award for NHS-prioritised centrally-managed, pregnancy and childbirth systematic reviews: CPGS 10/4001/02

Differences between protocol and review

We amended the Types of interventionssection by the inclusion of the phrase 'or other interventions for preventing excessive weight gain in pregnancy'.

We amended the Background section by adding subheadings to make the background easier to read. We also updated the background by including the new IOM guidelines (Medicine 2009) and including the guidance for the care of overweight and obese women of the UK Centre for Maternal and Child Enquiries (CMACE 2010).

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Asbee 2009

MethodsRandomised controlled trial, set in resident obstetric clinic in Charlotte, North Carolina, USA.
Participants

Inclusion criteria: prenatal care established at 6-16 weeks of gestation, age 18-49 years, all prenatal care received at the Resident Obstetrics Clinic, English-speaking, Spanish-speaking, or both, and singleton pregnancy.

Exclusion criteria: BMI higher than 40, pre-existing diabetes, untreated thyroid disease, or hypertension requiring medication or other medical conditions that might affect body weight, delivery at institution other than Carolinas Medical Center Main, pregnancy ending in premature delivery (less than 37 weeks), and limited prenatal care (fewer than 4 visits).

Interventions

Intervention group (n = 57) received consistent program of dietary and lifestyle counselling. At the initial visit, participants met with a registered dietician to receive a standardised counselling session, including information on pregnancy-specific dietary and lifestyle choices. The counselling consisted of recommendations for a patient-focused caloric value divided in a 40% CHO, 30% protein, and 30% fat fashion. Patients were instructed to engage in moderate-intensity exercise at least 3 times per week and preferably 5 times per week. They also received information on the appropriate weight gain during pregnancy using the IOM guidelines. Each participant met with the dietician only at the time of enrolment. At each routine obstetrical appointment, the healthcare provider informed the participant whether her weight gain was at the appropriate level. If her weight gain was not within the IOM guidelines, the participant’s diet and exercise regimen were reviewed and she was advised on increasing or decreasing her intake and increasing or decreasing exercise.

Control group (n = 43) received routine prenatal care, including an initial physical examination and history, routine laboratory tests, and routine visits per American College of Obstetricians and Gynecologists standards. The only counselling on diet and exercise during pregnancy was that included in a standard prenatal booklet. The healthcare provider did not counsel the participant regarding any changes in diet or lifestyle.

Outcomes

Weight gain, caesarean delivery, pre-eclampsia, shoulder dystocia.

Total weight gain was defined as weight just before delivery minus prepregnancy weight.

Notes

Age (intervention, control): 26.7 ± 6.0, 26.4 ± 5.0.

Enrollment gestational age (intervention, control): 13.7 ± 3.6, 13.6 ±.2 weeks.

Prepregnancy BMI: 25.5 ± 6.0, 25.6 ± 5.1 kg/m².

BMI category, n (intervention, control)

  • underweight and normal weight (BMI < 26): 35, 25;

  • overweight (BMI 26-29.0): 10, 8;

  • obese (BMI > 29.0): 12, 10.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandomisation was performed using computer-generated random allocation.
Allocation concealment (selection bias)Low riskStudy allocation was concealed in numbered and sealed opaque envelopes.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskNo information provided.
Incomplete outcome data (attrition bias)
All outcomes
Low risk

No loss to follow-up reported.

Trial authors stated that they had carried out an intention-to-treat analysis: data were analysed for participants according to their randomly-allocated group; all participants were included in the analysis.

Selective reporting (reporting bias)Low riskThe outcomes reported as in the published protocol.
Other biasLow risk

Demographic data were similar. Age, prepregnancy weight, height and BMI were not different at baseline.

No other obvious bias.

Barakat 2011

MethodsRandomised controlled trial, set in Hospital de Fuen-labrada, Madrid, Spain.
Participants

80 women randomised.

Inclusion criteria: healthy pregnant women (age, 23-38 years), had uncomplicated, singleton pregnancies.

Exclusion criteria: any type of absolute obstetric contraindication to aerobic exercise during pregnancy, which included other contraindications that the authors considered to have a relevant influence on maternal perception of health: significant heart disease, restrictive lung disease, incompetent cervix/cerclage, multiple gestation, risk of premature labour, pre-eclampsia/pregnancy-induced hypertension, thrombophlebitis, recent pulmonary embolism (last 5 years), acquired infectious disease, retarded intrauterine development, serious blood disease, and/or absence of prenatal care.

Interventions

Intervention group: (40 randomised) moderate physical activity, included a total of 35- to 45-minute weekly sessions 3 days each week from the start of the pregnancy (weeks 6-9) to the end of the 3rd trimester (weeks 38-39), an average of 85 training sessions, exercise intensity was light-to-moderate. Exercise was supervised by a fitness specialist and was in groups of 10-12 women.

Control group: (40 randomised) routine care.

OutcomesWeight gain, caesarean, birthweight < 4000 gm, birthweight > 4000 gm.
Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandomly assigned by use of a random number table.
Allocation concealment (selection bias)Unclear riskNot described.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskNot mentioned. It would be difficult to blind women and staff to this type of intervention. It is not clear how lack of blinding would impact on the outcomes measured.
Incomplete outcome data (attrition bias)
All outcomes
Unclear risk80 women were randomised and 67 were analysed; 34 in the exercise group, 33 in the control group. Reason of discontinued were similar in both groups.
Selective reporting (reporting bias)Unclear riskAssessment from published study report.
Other biasUnclear riskNo between-group differences regarding potential confounding variables (such as occupational activities, standing, smoking habits, alcohol intake). Parity was not balanced between groups; the exercise group had a higher percentage of nulliparous women (76.5%) than the control group (36.4%).

Bechtel-Blackwell 2002

MethodsA prospective, quasi-experimental design, set in an adolescent prenatal clinic in USA.
ParticipantsAdolescent African American women aged 13-18 years were recruited during 1st trimester or early 2nd trimester.
Interventions

Intervention group (n = 22): the nutrition education intervention consisted of 3 20-minute group sessions that addressed nutritional needs specific to the women's stage of pregnancy.

Control group (n = 24): standard care for nutritional counselling.

Both groups received a nutrition assessment using a computer-assisted self-interview in 1st, 2nd, and 3rd trimesters.

OutcomesWeight gain, weight retention at 6 weeks' postpartum.
NotesThe data of weight gain were reported in terms of weight gain during the 1st, 2nd and 3rd trimester with no SDs reported.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskParticipants were randomly assigned to groups.
Allocation concealment (selection bias)High riskQuasi-randomisation.
Blinding (performance bias and detection bias)
All outcomes
Low riskGroup members would be unable to distinguish who was in the experimental group.
Incomplete outcome data (attrition bias)
All outcomes
High risk

Loss to follow-up 23%; 26% in intervention group, 20% in control group.

Not provided information on reasons for loss to follow-up.

Selective reporting (reporting bias)Unclear riskCould not determine.
Other biasLow riskMaternal background characteristics revealed no statistically significant differences between groups.

Boileau 1968

MethodsRandomised controlled trial, place of study not stated.
ParticipantsPrivate patients in the 2nd trimester who were accumulating weight more rapidly and appeared to be excessively overweight at the beginning of pregnancy. Exclusion criteria were not reported.
Interventions

Intervention (n = 53): diethylpropion hydrochloride, 75 mg.

Control (n = 53): placebo.

OutcomesWeight change at each stage of gestation.
Notes

No SD for mean outcomes were reported.

Age (intervention, control): 26.3, 26.4.

Enrollment gestational age (intervention, control): 25, 25 weeks.

BMI before pregnancy (intervention, control): 25.3, 23.8 kg/m².

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided.
Allocation concealment (selection bias)Unclear riskNo information provided.
Blinding (performance bias and detection bias)
All outcomes
Low riskNeither the investigators nor the patients knew the content of the bottle.
Incomplete outcome data (attrition bias)
All outcomes
Unclear riskCould not determine.
Selective reporting (reporting bias)Unclear riskCould not determine.
Other biasLow riskBaseline data showed the 2 groups were comparable.

Callaway 2010

MethodsRandomised controlled trial, set in a hospital in Brisbane, Australia.
Participants

50 women randomised.

Inclusion criteria: obese pregnant women were recruited at 12 weeks’ gestation, aged 18-45, BMI ≥ 30  kg/m2,  pregnancy care at study hospital, willing and able to be randomised to an exercise intervention.

Exclusion criteria: non-English  speaking, contraindication or inability to exercise, medical or obstetric contraindication to exercise including haemodynamically significant heart disease, restrictive lung disease, incompetent cervix (cerclage), multiple  gestation, severe anaemia, chronic bronchitis, type 1 diabetes, orthopaedic limitations, poorly controlled seizure disorder, poorly controlled hyperthyroidism, or a heavy smoker.

Interventions

Intervention group: the intervention group received an individualised exercise program with an energy expenditure (EE) goal of 900 kcal/ week. Advice from physiotherapist and diaries for self-monitoring.

Control group: routine obstetric care.

OutcomesSelf-report of exercise (behaviour change).
Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandomisation was by a random number allocation technique conducted by a 3rd party.
Allocation concealment (selection bias)Unclear riskNot clear but external randomisation.
Blinding (performance bias and detection bias)
All outcomes
High riskNo blinding.The impact of the lack of blinding was not clear. The use of self-monitoring diaries by the intervention group may have introduced recall bias.
Incomplete outcome data (attrition bias)
All outcomes
High riskRandomised 50 women, at 36 weeks 36 were followed up (30% attrition).
Selective reporting (reporting bias)Unclear riskAssessment from published study report and on-line supplement.
Other biasUnclear riskThere were no statistically significant differences between the intervention and control groups in any baseline variable. Different monitoring techniques in the 2 groups (diaries in the intervention group) may have led to recall bias.

Clapp 2002

MethodsA prospective randomised design.
Participants20 healthy women with uncomplicated pregnancy.
InterventionsThe participants were enrolled prior to pregnancy and placed on a regular regimen of supervised exercise and began a weight maintaining diet (low glycaemic sources of CHO). At 8 weeks' gestation, they were randomised to either diet containing low glycaemic CHO sources(n = 10) (aboriginal CHO diet) or high glycaemic CHO sources (n = 10) (cafeteria CHO diet). All continued the same exercise regimen throughout pregnancy.
Outcomes

Weight gain.

Total weight gain was defined as weight at delivery minus prepregnancy weight.

NotesDuring pregnancy, all women were allowed to increase caloric intake according to appetite with advancing gestation.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNot described.
Allocation concealment (selection bias)Unclear riskNo information provided.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskNo information provided.
Incomplete outcome data (attrition bias)
All outcomes
Unclear riskUnspecified loss to follow-up.
Selective reporting (reporting bias)Unclear riskNo information provided.
Other biasUnclear riskNo information provided.

Clapp 2002a

MethodsRandomised controlled trial, set in Case Western Reserve University at metro health medical centre, USA.
Participants

Inclusion criteria: 80 healthy, regularly exercising (≥ 3 times/week), non-substance-abusing women were enrolled before pregnancy.

After conception (which occurred within 4 months in all cases) and ultrasonic confirmation of a viable singleton pregnancy, these women were assigned in week 8 of gestation to the exercise regimens.

Exclusion criteria: not stated.

Number of participants: 75 women enrolled and complete the protocol; 26 in Lo-Hi group, 24 in Mod-Mod group, 25 in Hi-Lo group.

Interventions

There were 3 study groups:

group 1: low-high exercise (n = 26): exercise 20 minutes 5 days a week through to week 20, gradually increasing to 60 minutes 5 days a week by week 24 and maintaining that regimen until delivery (Lo-Hi).

group 2: moderate-moderate exercise (n = 24): exercise 40 minutes 5 days a week from week 8 until delivery (Mod-Mod).

group 3: high-low exercise (n = 25): exercise 60 minutes 5 days a week through to week 20, gradually decreasing to 20 minutes 5 days a week by week 24 and maintaining that regimen until delivery (Hi-Lo).

OutcomesWeight gain.
NotesAge 31 ± 1, 30 ± 1, 32 ± 1 in Lo-Hi, Mo-Mo, Hi-Lo.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskWomen were randomly assigned.
Allocation concealment (selection bias)Unclear riskWomen were randomly assigned by envelope but it was not stated whether envelopes were sequentially numbered, opaque and sealed.  
Blinding (performance bias and detection bias)
All outcomes
High riskA member of the study team carried out morphometric assessment of placenta and infant at the time of birth.                                                                                       
Incomplete outcome data (attrition bias)
All outcomes
Low riskLoss to follow-up 6.25%.                           
Selective reporting (reporting bias)Unclear riskCould not determine.
Other biasLow riskBaseline data were similar.

Guelinckx 2010

MethodsRandomised controlled trial, set in the prenatal clinic, University Hospital of Leuven, Belgium.
Participants

Inclusion criteria: obese (BMI > 29.0 according to IOM criteria), white women consecutively attending the prenatal clinic before 15 week of gestation.

Exclusion criteria: preexisting diabetes or developing GDM, multiple pregnancy, recruitment after 15 week of gestational age, premature labour (delivery before 37 week of gestation), primary need for nutritional advice in case of a metabolic disorder, kidney problems, Crohn's disease, allergic conditions, and inadequate knowledge of the Dutch language.

Interventions

2 intervention groups: the passive group (n = 37): received a brochure during the 1st prenatal consultation. This brochure was specifically designed for the study and provided advice on nutrition and on physical activity and tips to limit pregnancy-related weight gain. The active group (n = 42): received the same brochure and women were actively counselled by a trained nutritionist in 3 group sessions. A maximum of 5 women were brought together in these 1-hour sessions, which were scheduled at 15, 20, and 32 weeks of pregnancy. The sessions provided subjects with recommendations on a balanced, healthy diet, based on the Official National Dietary Recommendations (9–11% of the energy should come from proteins, 30–35% from fat, and 50–55% from CHOs).

Control group (n = 43): received routine prenatal care.

(Energy intake was not restricted in any group.)

Outcomes

Excessive weight gain (weight gain more than the upper limit recommendation for overweight women; > 11.2 kg).

Gestational weight gain.

Obstetrical and neonatal outcome: pre-eclampsia, induction of labour, caesarean section, birthweight > 4000 gm.

Average energy intake.

Weight gain was defined as weight at birth minus prepregnancy weight.

Total physical activity score at 3rd trimester.

For analysis 3.10 and 4.10 a physical activity score was calculated by using a questionnaire including a total 16 questions classified into 3 domains: work, sports, and non-sports leisure-time activities, scored on a 5-point scale, ranging from “never”, “seldom”, “sometimes”, “very often”, to “always”.  A total score for physical activity from a minimum of 3 to a maximum of 15 was obtained. A higher score indicated more activity.

Notes

Age 29.4 ± 4.4, 28.7 ± 4.0, 28.0 ± 3.6 years for control group, passive group, active group.

Enrollment gestational age: 10.2 ± 2.4, 10.2 ± 2.6, 9.3 ± 2.8 weeks for control group, passive group, active group.

Prepregnancy BMI: 33.5 ± 3.9, 33.4 ± 3.07, 34.1 ±4 .5 kg/m2 for control group, passive group, active group.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided.
Allocation concealment (selection bias)Low riskPatients were randomly assigned by using block randomisation.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskNo information provided.
Incomplete outcome data (attrition bias)
All outcomes
Low risk

Loss to follow-up 9.7%.

Reasons for excluding the participants from each group were similar.

Selective reporting (reporting bias)Unclear riskCould not determined.
Other biasLow riskBaseline characteristics of participants were similar between intervention and control groups.

Huang 2011

MethodsRandomised controlled trial; 3 groups intervention design; 2 experimental groups (from pregnancy to 6 months postpartum (EP) and from birth to 6 months postpartum (EPP). The group receiving the intervention in the postnatal period only is not included in our analysis) and 1 comparison group.
Participants

From January to June 2006, pregnant women were recruited from the obstetric clinics of a hospital in Taiwan. (160 women randomised.)

Inclusion criteria:16 gestational weeks, age 18 years or older, no cognitive impairment or psychiatric illness, ability to speak and read Chinese, not participating in another study, and intention to give birth at the study site.

Interventions

Intervention group: (80 participants).The educational intervention began at 16 gestational weeks (baseline) and to 6 months postpartum. The intervention was delivered at regularly scheduled clinic visits by nurses with training in nutrition and physical fitness. The nurse discussed with each participant how to design an individualised diet and physical activity plan. The intervention consisted of 6 1-to-1 counselling sessions: 1 primary session (about 30–40 minutes) at the 16-week gestation visit, and 5 1-to-1 booster sessions (at 28 gestational weeks, 36–38 gestational weeks, before hospital discharge after a 3–7-day stay, 6 weeks' postpartum and 3 months postpartum). After each clinic visit, women in the experimental groups were sent a personalised graph of their weight changes. At the 1st session, the experimental groups also received a researcher-prepared brochure that provided detailed information on weight management goals during pregnancy and postpartum.

Control group: (80 participants) routine care, provided once each trimester which health education on nutrition and exercise during pregnancy.

Outcomes

Gestational weight gain, weight retention at 6 months postpartum, health-promoting behaviour; physical activity.

For analysis 1.9.1 physical activity measurement was a part of the health-promoting lifestyle profile composed of 50-item scale uses a 4-point response format (range = 50–200) to measure the frequency of engaging in activities related to self-actualisation, nutrition, physical activity,interpersonal support, health responsibility and stress management.

Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskUsing a table of random numbers.
Allocation concealment (selection bias)Unclear riskNot stated.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskThe research assistant collecting outcome data was reported to be blind to the group assignments.
Incomplete outcome data (attrition bias)
All outcomes
Unclear risk80 women in each group were randomised, 61 and 64 of intervention and control group were analysed (78% followed up).
Selective reporting (reporting bias)Unclear riskAssessment from published study report.
Other biasLow riskNo notable baseline differences were found between groups.

Hui 2006

MethodsRandomised controlled trial, set in a community nurse-managed centre and the Manitoba Clinic, both in urban Winnipeg, Manitoba, Canada.
Participants

Inclusion criteria: women < 26 weeks pregnant with no pre-existing diabetes were recruited on a voluntary basis. 

Exclusion criteria: pregnant women who had medical obstetric, skeletal or muscular disorders that could contraindicate physical exercise during pregnancy.

Interventions

Intervention (n = 24): additional intervention: lifestyle intervention including exercise intervention and dietary intervention.

Exercise intervention: participants were instructed in group-session exercises and in home-based exercise. Weekly group session included floor aerobics, stretching and strength exercises, 3-5 times/week for 30-45 minutes per session, video provided to participants to assist with home-based exercise.

Nutrition intervention: computer-assisted food choice map interview, dieticians provided a personalised plan for participants.

Control (n = 21): standard care group received an information package on diet and physical activity for a healthy pregnancy.

Outcomes

Excessive weight gain, weight gain, cesarean section, infant birthweight > 4000 gm, and physical activity at end of study.

Weight gain was defined as weight at birth (from medical chart) minus prepregnancy weight.

For analysis 1.9.1 physical activity was defined as recreational physical activity which was measured by using the PARmed-X for Pregnancy form based on Health Canada recommendations. Low levels (physical activity = 0) are defined as either no physical activity or activity < 1 to 2 times per week and for < 20 min per session; moderate levels (physical activity = 1) are defined as activity 1 to 2 times per week and for > 20 min per session or > 2 times per week and for < 20 min per session; high level (physical activity = 2) are defined as activity > 2 times per week and for > 20 min per session.

Notes

Age (intervention, control): 26.2 ± 5.7, 26.2 ± 5.4.

Prepregnancy BMI (intervention, control): 25 ± 6.3, 23.4 ± 3.9 kg/m².

Excessive weight gain was assessed based on prepregnant BMI.

  • BMI < 20 kg/m², weight gain during pregnancy 12.5 -18 kg.

  • BMI 20-27 kg/m², upper limit of weight gain 16 kg.

  • BMI > 27 kg/m², upper limit of weight gain 11.5 kg.

(Canadian guidelines for healthy weights.)

Majority of participants (89%) were from low-income families or low-middle income families.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskParticipants were enrolled and randomised into additional intervention and standard care groups.
Allocation concealment (selection bias)Unclear riskNo information provided.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskNo information provided.
Incomplete outcome data (attrition bias)
All outcomes
High risk

52 enrolled, 45 completed. Loss = 7/52*100 = 13.5%. 

7 pregnant women dropped out due to school or work commitments.

The participants who dropped out were significantly younger and had lower incomes than those who completed the program (P < 0.01).

Selective reporting (reporting bias)Unclear riskCould not determine.
Other biasLow riskNo significant differences were found in age, prepregnancy BMI, and family income between additional intervention and standard care groups.

Jackson 2011

MethodsRandomised controlled trial, set in 5 prenatal care practices in the San Francisco Bay Area, USA, including 3 public hospitals, 2 academic practices, and a community hospital. 2006-2007.
Participants

327 women randomised.

Inclusion criteria: English-speaking women 18 years or older and less than 26 weeks of gestation.

Exclusion criteria: women who report smoking, alcohol use, drug use, or partner violence.

Interventions

Intervention group: (163 randomised) The Video Doctor: an interactive computer program including in-depth behavioural risk assessments and tailored counselling messages, and producing printed output for both the patient and clinician. An actor-portrayed Video Doctor appears and offers education on exercise, nutrition and weight gain based on principles of Motivational Interviewing. Dietary counselling focused on increasing intake of fruits and vegetables and whole grains, increasing healthful versus unhealthful fats and decreasing sugary foods. The Video Doctor emphasised dietary and exercise behaviour changes over weight gain. The Video Doctor programme required 10–15 minutes to complete. After 4 weeks, participants received a brief ‘‘booster’’ Video Doctor counselling.

Control group: (164 randomised) usual care. The usual care group did not interact with the Video Doctor and the program did not produce a Cueing Sheet or Educational Worksheet. Behavioural counselling for the usual care group was determined by the clinician.

OutcomesSelf-reported servings per day or week of healthful foods (e.g. fruits and vegetables) and unhealthful foods (e.g. sweets), and exercise duration and frequency, and weight gain above the IOM guidelines.
Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandomisation by computer.
Allocation concealment (selection bias)Low riskRandomisation by computer (interactive computer programme intervention).
Blinding (performance bias and detection bias)
All outcomes
Unclear riskParticipants would not be blind to the intervention. It was not stated that staff or outcome assessors were blinded.
Incomplete outcome data (attrition bias)
All outcomes
Low risk6 women were excluded after randomisation: 3 due to insufficient English, 1 because of inaccurate gestational age, and 2 withdrew during the baseline assessment leaving 158 in the Video Doctor group and 163 in the usual care group. Intention-to-treat analysis was performed for primary outcome (weight gain) for other outcomes 327 were randomised and 287 (88%) completed follow-up.
Selective reporting (reporting bias)Unclear riskAssessment from published study report.
Other biasUnclear riskThere were no significant differences between the control and Video Doctor groups for any of the demographic variables listed except education. Results for weight gain were not fully reported by randomisation group. Results for  mean weight gain of each group were reported without SDs.

Jeffries 2009

MethodsRandomised controlled trial, set in a tertiary obstetric hospital in Melbourne, Australia.
Participants

Inclusion criteria: pregnant women at < 14 weeks' gestation.

Exclusion criteria: age < 18 or > 45 years, type 1 or type 2 diabetes mellitus, multiple pregnancy, or non-English speaking.

Interventions

Intervention (n = 125): women allocated to the intervention group were given a personalised weight measurement card, advised of their optimal gestational weight gain (based on their BMI at the time of recruitment and the United States IOM guidelines, and instructed to record their weight at 16, 20, 24, 28, 30, 32 and 34 weeks' gestation.

Control (n = 111): not given instructions about regular weight measurement.

Outcomes

Weight gain above IOM guideline, mean weight gain from recruitment to follow-up at 36 weeks' gestation.

Small-for-gestational age (< 10th centile), large-for-gestational age (> 90th centile), preterm (< 37 weeks), instrumental delivery, caesarean delivery, pre-eclampsias, neonatal hypoglycaemia, shoulder dystocia.

Weight gain was weight difference between weight at about 36 weeks' gestation and weight at 1st antenatal appointment.

Notes

Gestation age at recruitment (intervention, control): 11.6, 11.4 weeks.

BMI category, n (intervention, control):

  • underweight (BMI ≤ 19.8): 5, 5;

  • normal (BMI > 19.8, ≤ 26.0): 75, 67;

  • overweight (BMI > 26, ≤ 29.0): 20, 18;

  • obese (BMI > 29.0): 25, 21.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskUsing computer random number generation.
Allocation concealment (selection bias)Low riskUsing opaque, sequentially numbered envelopes.
Blinding (performance bias and detection bias)
All outcomes
Low riskAll participants were blinded to the purpose of the study.
Incomplete outcome data (attrition bias)
All outcomes
Low risk

Loss to follow-up, 23/148 in intervention group, 27/138 in control group.

Similar reason of loss to follow-up in intervention and control groups.

Selective reporting (reporting bias)Low riskThe outcomes reported as in the published protocol.
Other biasLow riskBaseline characteristics were similar.

Korpi-Hyovalti 2011

MethodsRandomised controlled trial, set in 2 hospitals in rural municipalities (Kauha-joki and Lapua) in Finland.
Participants

60 women randomised.

Inclusion criteria: women at high risk of gestational diabetes: women had 1 or more risk factors (BMI > 25 kg/m2, previous history of GDM or birth of child > 4.5 kg, age > 40 years, family history of diabetes or the venous plasma glucose concentration after 12 hours fasting in the morning was 4.8-5.5 mmol/L and 2-hour OGTT plasma glucose < 7.8 mmol/L.

Exclusion criteria: women who were diagnosed as having GDM in this study and women who had risk factors for GDM or whose fasting venous plasma glucose was 4.8-5.5 mmol/L but who for personal or professional reasons did not wish to participate in the trial.

Interventions

Intervention group: (n = 30) a lifestyle intervention; included diet counselling and exercise counselling. Dietary advice tailored to each subject individually on 6 occasions. Women were encouraged to eat a diet rich in vegetables, berries and fruits, and to use low-fat. Moderate-intensity physical exercise during pregnancy was encouraged, 6 sessions for exercise counselling.

Control group: close follow-up group (n = 30). All women were given general information on diet and physical activity to decrease the risk of GDM during pregnancy as part of routine care.

OutcomesWeight gain.
Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskWomen were randomly assigned to the lifestyle intervention group or to the close follow-up group by the study physician in the Central Hospital with the use of a computed randomisation list.
Allocation concealment (selection bias)Unclear riskNot stated.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskWomen would be aware of group assignment although it was stated that the nurses scheduling study visits did not have access to the randomisation list. It is not clear what impact the lack of blinding would have on the outcomes measured.
Incomplete outcome data (attrition bias)
All outcomes
Unclear risk60 women were randomised, 54 were followed up.
Selective reporting (reporting bias)Unclear riskAssessment from published study report.
Other biasUnclear riskThere were no statistically significant differences in baseline measures between the lifestyle intervention and the close follow-up groups although women in the intervention group had slightly higher prepregnancy weight (mean 76.6 compared with 69.6 in controls.

Laitinen 2009

MethodsRandomised controlled trial, set in maternal welfare clinics in the city of Turku and neighbouring areas in south-west Finland.
Participants

Women were eligible for participation if they were less than 17 weeks’ gestation and had no metabolic or chronic diseases such as diabetes.

Participants were Caucasian.

Interventions

At 1st trimester 256 pregnant women were allocated to 3 groups: modification of dietary intake according to current recommendations with probiotics or placebo and a control group receiving placebo only.

  1. Control group, (placebo) (n = 85).

  2. Intervention group 1 (n = 86) (diet counselling and placebo).

  3. Intervention group 2 (n = 85) (diet counselling and probiotics), probiotic capsules containing Lactobacillus rhamnosus GG and Bifidobacterium lactis Bb12.

Dietary counselling given by a dietitian at each study visit aimed to modify dietary intake to conform with that currently recommended, particular attention being paid to the quality of dietary fat.

Study visits took place 3 times during pregnancy at 13·9 (SD 1·6), 23·8 (SD 1·4) and 33·9 (SD 1·4) weeks of gestation and at 1, 6 and 12 months postpartum.

Outcomes

Weight gain, energy intake, dietary fibre intake at 3rd trimester of pregnancy.

Weight gain was calculated by subtracting self-reported prepregnancy weight from that recorded at a prenatal visit or at hospital within 1 week before delivery.

NotesAge (intervention 1, intervention 2, control): 30.1 ± 5.2, 29.7 ± 4.1, 30.2 ± 5.0.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskSubjects were randomly assigned to 3 study groups according to computer-generated block randomisation.
Allocation concealment (selection bias)Low riskUsing sealed envelopes. At the 1st study visit the envelopes were opened. The random allocation sequence was thus concealed until interventions were assigned.
Blinding (performance bias and detection bias)
All outcomes
Low riskIntervention groups took place in a double-blind manner, while the control group received placebo in single-blind manner.
Incomplete outcome data (attrition bias)
All outcomes
Low riskNo loss to follow-up (to delivery).
Selective reporting (reporting bias)Low riskThe outcomes reported as in the published protocol.
Other biasLow riskNo other bias apparent.

Luoto 2011

MethodsCluster-randomised controlled trial, set in primary healthcare centres in 14 municipalities in Pirkanmaa region in south-western Finland.
Participants

Recruitment 2007-8.

Inclusion criteria: Pregnant women at 8–12 weeks' gestation at high risk of developing gestational diabetes;  BMI ≥ 25 kg/m² based on measured height and self-reported prepregnancy weight; GDM or any signs of glucose intolerance or newborn’s macrosomia (≥ 4500 gm) in any earlier pregnancy; type 1 or 2 diabetes in 1st- or 2nd-degree relatives; or age ≥ 40 years.

Exclusion criteria: at least 1 of the 3 baseline (8–12 weeks' gestation) OGTT measurements was abnormal (fasting blood glucose ≥ 5.3 mmol/L, 10.0 mmol/L at 1 hr, and 8.6 mmol/L at 2 hr); prepregnancy type 1 or 2 diabetes; inability to speak Finnish; age <18 yr; multiple pregnancy; physical restriction preventing physical activity; substance abuse; treatment or clinical history of psychiatric illness.

Interventions

Intervention group: (7 municipalities) Individual counselling on physical activity and diet and weight gain. At the 1st visit the recommendations for gestational weight gain were discussed and an appropriate weight gain graph was selected to guide the participant in monitoring her weight gain. The primary physical activity counselling was implemented at 8–12 weeks' gestation and the primary dietary counselling session at 16–18 weeks' gestation. Physical activity counselling was enhanced at 4, and diet counselling at 3 subsequent visits.

Control group: (7 municipalities) usual care group received no counselling beyond usual care, which included some dietary counselling (partly on different topics) and follow-up of gestational weight, but little physical activity counselling.

OutcomesIncidence of GDM as assessed by OGTT (maternal outcome) and newborns’ birthweight adjusted for gestational age, maternal weight gain and the need for insulin treatment during pregnancy, changes in physical activity and diet (intake of total fat, saturated and polyunsaturated fatty acids, saccharose, and fibre.
Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskThe unit of randomisation was municipality. In the randomisation process, participating municipalities were 1st pair-wise matched. 14 municipalities were then randomised by computer.
Allocation concealment (selection bias)Low riskCluster-randomised trial with computer randomisation.
Blinding (performance bias and detection bias)
All outcomes
Unclear risk

The impact of lack of blinding in this trial is unclear.

Women would be aware of intervention and so would staff. Women in the intervention group were provided with notebooks to record diet and activity, women in the control group were not; this may have affected recall and may have introduced bias. It was not clear whether staff collecting outcome data were blind to group assignment.

Incomplete outcome data (attrition bias)
All outcomes
High risk14 clusters were randomised and all were included in the analysis. 343 women in the intervention and 297 in the usual care group agreed to participate in the trial. However, 81 (23.6%) of the participants in intervention group and 93 (31.3%) of the participants in the usual care group had an abnormal OGTT result at baseline and were thus excluded. The final number of participants in the analyses was 219 (89.0% of participants receiving allocated intervention) in the intervention group and 180 (91.8% of participants receiving allocated intervention) in the usual care group. However about 40%of eligible participants of each group were followed up.
Selective reporting (reporting bias)Unclear riskAssessment from published study reports.
Other biasUnclear riskBaseline characteristics of each group were similar, except there were women in the intervention group with high education than in the usual care group. There was adjustment of data for clustering and various cluster, clinic and individual level differences at baseline.

Magee 1990

MethodsRandomised controlled trial, set in prenatal care at the University of Washington Obstetrics Clinics.
ParticipantsPregnant women with obesity (prepregnancy weight > 120% of ideal body weight) and diagnosed with gestational diabetes, recruited at 28 weeks' gestation.
Interventions

All patients were hospitalised for 2-week duration in the metabolic ward.

Intervention; calorie-restricted (n = 7): during the 1st week, the women consumed normal diet with 2400 kcal/day; 50% CHO, 30% fat and 20% protein with 11 gm of total dietary fibre per 500 kcal. During the 2nd week, the women were placed on 1200 kcal/day diet. This reduction was accomplished by decreasing portion sizes without changing other features of diet.

Control (n = 5): during the 1st week, the patients consumed identical diet as the intervention group; 2400 kcal/day, and continued on the same diet (2400 kcal/day) during the 2nd week.

Outcomes

Metabolic indices: fasting plasma glucose, OGTT, insulin, triglyceride, free fatty acids, glycerol, ß-hydroxybutyrate, and urine ketones.

We have not included outcome data from this hospital inpatient study in the analyses in the review.

NotesAge (calorie-restricted, control): 30 ± 4, 36 ± 5 years.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNo information provided.
Allocation concealment (selection bias)Unclear riskNo information provided.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskNo information provided.
Incomplete outcome data (attrition bias)
All outcomes
Unclear riskNo information provided.
Selective reporting (reporting bias)Unclear riskCould not determine.
Other biasUnclear riskNo information provided.

Moses 2006

MethodsQuasi-randomised controlled trial, set in antenatal clinic at Wollongong Hospital, Wollongong, NSW, Australia.
Participants

Inclusion criteria: healthy, pregnant women from the antenatal clinic at Wollongong Hospital and from 2 obstetricians in private practice. They were aged 21– 40 years, had a singleton pregnancy, were between 12 and 16 weeks' gestation, were nonsmokers, and consumed no more than 1 alcoholic drink each day.

Exclusion criteria: any problem associated with glucose metabolism or insulin resistance or that interfered with the ability of the study participant to follow dietary instructions.

Interventions

Participants were randomised to a low glycaemic diet or high glycaemic diet.

Low glycaemic diet (n = 32): seen by dietitian 5 times during pregnancy, received dietary recommendation for low GI diet with 33% fat, 55% CHO. The low GI diet was based on verified low-GI foods, including pasta and brand-name breads and breakfast cereals with a high fibre content.

High glycaemic diet (n = 30): also seen by dietitian 5 times during pregnancy, received dietary recommendation for moderate-to-high GI diet (high fibre, low sugar) with 33% fat, 55% CHO.

OutcomesWeight gain (from 12 weeks to 36 weeks), large-for-gestational age (> 90th centile for birthweight), small-for-gestational age (< 10th centile for birthweight).
Notes

Age (low GI, high GI): 30.1 ± 0.7, 29.6 ± 0.7.

BMI at baseline (low GI, high GI): 24.4 ± 0.7, 26.6 ± 0.9 kg/m².

The baseline visit was between 12-16 weeks' gestation.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)High riskAlternation.
Allocation concealment (selection bias)High riskAlternate allocation to study groups.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskNo information provided.
Incomplete outcome data (attrition bias)
All outcomes
Low risk

Loss of participants to follow-up: In the low–GI diet group, 2 women withdrew due to being unwilling to follow the diet and 1 delivered before the final visit. In high-GI diet group, 1 woman was unwilling to follow the diet, 1 lost to follow-up, and 3 miscarriages.

Intention-to-treat analysis: data were analysed for participants according to their randomly-allocated group, not all original participants were included in the analysis.

Selective reporting (reporting bias)Unclear riskCould not determine.
Other biasLow riskBaseline characteristics were similar.

Moses 2009

MethodsRandomised controlled trial, set in the city of Wollongong, New South Wales, Australia.
Participants

Inclusion criteria: pregnant women, age 18–40 years (inclusive), singleton pregnancy, no previous GDM, nonsmoker, diagnosis of GDM and seen for the 1st dietary visit between 28 and 32 weeks of gestation, and ability to follow the protocol requirements.

Exclusion criteria: any condition or medication that could affect glucose levels and unwillingness to follow the prescribed diet.

Interventions

63 women were randomly assigned to receive 1 of 2 different diets, low–GI diet (n = 31) or higher–GI diet (n = 32). Both diets were compatible with the recommended nutritional intake in pregnancy. The CHO intake was designed to achieve a minimum of 175 gm/day with only the recommended choice of CHO foods varying. The dietary advice by dietitian was individualised with specific mention of the energy and nutrient balance to achieve normal weight gain during the 3rd trimester.

The low–glycaemic diet: based on previously verified low–GI food, including pasta, grain breads, and unprocessed breakfast cereals with a high fibre content. Women were specifically asked to avoid consuming white bread, processed commercial breakfast cereals, potatoes, and some rice varieties.

The higher–glycaemic diet: a diet with a high-fibre and low-sugar content, with no specific mention of the GI. Potatoes, whole wheat bread, and specific high-fibre, moderate-to-high–GI breakfast cereals were recommended.

OutcomesInduction of labour, method of delivery, large-for-gestational-age baby (> 90th centile), small-for-gestational-age baby (< 10th centile).
Notes

Age (LGI, HGI): 30.8 + 0.7, 31.3 + 0.8.

Gestational age at entry to study (LGI, HGI): 30.3 + 0.2 weeks, LGI 29.9 + 0.2 weeks.

BMI at enrolment (LGI, HGI): 32.0, 32.8 kg/m².

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskWomen were randomly assigned using permuted blocks of unequal size with the list generated using STATA (version 7.0).
Allocation concealment (selection bias)Unclear riskNot stated.
Blinding (performance bias and detection bias)
All outcomes
Low risk

The physician caring for the patients was blinded.

Study dietitians were not blinded to dietary assignment but were aware of the need for impartiality and equivalent treatment.

Participants were impossible to blind to the GI concept, as it is widely known and discussed in the lay press.

Incomplete outcome data (attrition bias)
All outcomes
Low riskNo drop-out apparent.
Selective reporting (reporting bias)Unclear riskCould not determine.
Other biasLow riskThere were no significant differences in the baseline characteristics of the 2 groups.

Phelan 2011

MethodsRandomised controlled trial, 2 arms with individual randomisation (stratified by prepregnancy weight, set in 6 obstetric offices in Providence, Rhode Island, USA  from 2006 to 2008.
Participants

401 women randomised.

Inclusion criteria: gestational age between 10 and 16 weeks, BMI between 19.8 and 40, nonsmoking , adults (aged > 18 yr), fluency in English, access to a telephone, and a singleton pregnancy.

Exclusion criteria: major health or psychiatric diseases, weight loss during pregnancy, or a history of ≥ 3 miscarriages.

Interventions

Intervention group: standard care plus a behavioural lifestyle intervention. The Fit for Delivery intervention included a face-to-face visit with an interventionist at the onset of treatment who discussed appropriate weight gains during pregnancy, physical activity (30 min of walking most days of the week), and calorie goals (20 kcal/kg); emphasis was placed on decreasing high fat foods, increasing physical activity, and daily self-monitoring of eating, exercise, and weight. Body-weight scales, food records, and pedometers were provided to promote adherence to daily self-monitoring. Automated postcards that prompted healthy eating and exercise habits were mailed weekly. In addition, after each clinic visit, women were sent personalised graphs of their weight gains with feedback. All women in the intervention received 3 brief (i.e., 10–15 min) supportive phone calls from the dietitian during the intervention. Women who were over or under weight-gain guidelines during any 1 month interval received additional brief, supportive phone calls (2 calls/mo) that provided structured meal plans, and specific goals until weight gains returned to appropriate amounts.

Control group: routine care. Women received standard nutrition counselling provided by physicians, nurses, nutritionists, and counsellors. As part of routine care women were weighed by nurses at each clinical visit; weight graphs were not provided.

OutcomesExcessive weight gain, low weight gain, preterm birth, pre-eclampsia or eclampsia, caesarean delivery rate, high birthweight, low birthweight, maternal weight retention.
Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandomisation was computer-generated in randomly varying block sizes and stratified by clinic and BMI category.
Allocation concealment (selection bias)Low riskAllocation was concealed in opaque envelopes prepared by the study statistician.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskUnblinded study research coordinator enrolled and randomly assigned participants into groups. In the abstract it was stated that outcome assessors were blinded.
Incomplete outcome data (attrition bias)
All outcomes
Low risk

Lost to follow-up 34 in the standard care group, 36 in the intervention group. Exclusions: 18  in the standard care group, 25 in the intervention group.

401 participants were randomly assigned into the intervention (n = 201) and control groups ( n = 200), included in 6 month postpartum analysis; 182 control, 176 intervention.

ITT analysis was performed assuming that those lost to follow-up were treatment failures. It was reported that this revealed almost identical results as for those completing the study (data not shown).

Selective reporting (reporting bias)Unclear riskAssessment from published study report.
Other biasUnclear riskThe 2 study groups did not significantly differ on key baseline measures (sample stratified).

Polley 2002

MethodsRandomised controlled trial, set in an obstetric clinic for low-income women at a hospital in Pittsburgh, PA, USA.
Participants

Inclusion criteria: pregnant women before 20 weeks of gestation. (Subjects were recruited in to 4 cells; normal and overweight, black and white.) 

Exclusion criteria: underweight women, younger than 18 years, 1st prenatal visit > 12 weeks' gestation, high-risk pregnancy (i.e.. drug abuse, chronic health problems, previous complications during pregnancy, current multiple gestation).

Interventions

Intervention (n = 57): the intervention was provided at regular scheduled clinic visits by staff with training in nutrition or clinical psychology. Education about weight gain, healthy eating, and exercise and individual graphs of their weight gain.

Shortly after recruitment, written and oral information were given in the following area: appropriate weight gain, exercise, healthy eating.Newsletters prompting healthy eating and exercise habits were mailed bi-weekly. After each clinic visit, women were sent a personalised graph of their weight gain.

Those exceeding weight gain goals were given additional individualised nutrition and behavioural counselling using the format listed; a stepped care approach.

Control (n = 53): usual care: standard nutrition counselling provided by the physicians, nurses, nutritionists and WIC counsellors. This counselling emphasised a well-balanced dietary intake and advice to take a multivitamin/iron supplement.

Outcomes

Excessive weight gain, total weight gain, low weight gain.

Low birthweight infants, macrosomia infants, preterm delivery, caesarean delivery, pre-eclampsia, weight retention at 4 weeks' postpartum.

Total weight gain was based on self-reported prepregnancy weight and weight at last clinic visit prior to delivery.

Notes

Excessive weight gain categorised as above the IOM recommendations.

Low weight gain categorised as below the IOM recommendations.

IOM recommends a weight gain of 6.8-11.3 kg for overweight women (BMI of 26-29) and a weight gain of 6.8 kg (with no specified upper limit) for obese women (BMI > 29).

Age of participants 25.5 ± 4.8.

Gestational age at recruitment (intervention, control): 14.7 ± 3.1 weeks.

BMI category, n (intervention, control):

  • normal weight (BMI19.8-26): 30, 31;

  • overweight (BMI > 26): 27, 22.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskWomen were randomly assigned to the standard care control group or to the intervention.
Allocation concealment (selection bias)Unclear riskNo information provided.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskNo information provided.
Incomplete outcome data (attrition bias)
All outcomes
Low risk

Using intention-to-treat approach.

Loss to follow-up < 10%.

Selective reporting (reporting bias)Unclear riskCould not determine.
Other biasHigh riskRefusal rates were higher among black women (28/74 refused) than among white (16/90 refused), and higher in overweight black women than in any of the other 3 weight-by-race categories.

Quinlivan 2011

MethodsRandomised controlled trial, set in the maternity service of a public general hospital serving a socioeconomically disadvantaged area in Melbourne, Australia.
Participants

132 randomised.

Inclusion criteria: pregnant with a fetus with no known anomalies, spoke English, did not intend to relinquish their infant, did not have a multiple gestation, were able to attend hospital for antenatal care and were overweight (BMI 25–29. 9) or obese (BMI > 29 .9).

Exclusion criteria: not described.

Interventions

Intervention group: a 4-step multidisciplinary protocol of antenatal care which had the following 4 criteria : (i) continuity of care provider; (ii) weighing on arrival; (iii) brief dietary intervention by a food technologist at every antenatal visit; and (iv) psychological assessment. Women attended special study clinics.

Control group: routine care (with access to high-risk clinics if medically indicated).

OutcomesWeight gain, preterm delivery.
Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandomisation to the intervention or control groups occurred using computer-generated sequence.
Allocation concealment (selection bias)Low riskNumbered sealed opaque envelopes, stratified by category (overweight or obese;16), which were only opened by the midwife after each woman’s enrolment was completed.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskOutcome data for mother and infant were audited by a nurse independent of clinical care pathways and blinded to randomisation status.
Incomplete outcome data (attrition bias)
All outcomes
Low risk132 randomised, 124 analysed (8 excluded from analysis (4 of each group).
Selective reporting (reporting bias)Unclear riskAssessment from published study report.
Other biasUnclear risk

There were no significant differences in terms of antenatal, demographic and health behaviour variables between intervention and control groups.

Women in the intervention group attended special study clinics; these clinics may have been different from standard clinics in more ways than the intended study interventions (although it was stated that care was standard apart from the 4 stage intervention).

Rae 2000

MethodsRandomised controlled trial, set in the Diabetes Service, King Edward Memorial Hospital for Women, Perth, Western Australia.
Participants

Inclusion criteria: gestation < 35 weeks and 6 days, > 110% of ideal body weight for height (adjusted for expected pregnancy weight gain and using a BMI of 25 as equal to 100% ideal body weight), OGTT with fasting plasma glucose > 5.4 mmol/L and/or 2 hour plasma glucose > 7.9 mmol/L.

Exclusion criteria: not stated.

Interventions

Intervention (n = 63): the intervention comprised instruction in a moderately energy restricted diabetic diet providing between 1590-1776 kcal (70% RDA).

Control (n = 54): the control group were instructed in a diabetic diet which was not energy restricted, providing approximately 2010-2220 kcal a day.

Outcomes

Weight gain, pre-eclampsias, induction of labour, caesarean delivery, shoulder dystocia, birthweight > 4000 gm, birthweight > 90th centile, assisted delivery.

Weight gain was calculated as the difference between prepregnancy weight and delivery weight.

Notes

Age (intervention, control) 30.2, 30.6 years.

Gestation at diagnosis(intervention, control) 28.1 ± 5.8, 28.3 ± 4.6 weeks.

BMI at diagnosis (intervention, control) 37.9 ± 0.7, 38.0 ± 0.7 kg/m².

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskNot stated.
Allocation concealment (selection bias)Low riskWomen were allocated at random using opaque numbered envelopes.
Blinding (performance bias and detection bias)
All outcomes
Low risk

Both participants and the Diabetes Service staff were blinded to the allocation to diet group. 

Medical staff were blinded to the group allocation of each participant.

Incomplete outcome data (attrition bias)
All outcomes
Low riskLoss to follow-up 6.4% (8), 4 for each group.         
Selective reporting (reporting bias)Unclear riskCould not be determined.
Other biasLow risk

The groups were similar in level of education, employment, racial distribution, and alcohol and cigarette consumption.

There were no significant differences at enrolment in weight, or energy expenditure.

Rhodes 2010

MethodsRandomised controlled trial (pilot study), set in Beth Israel Deaconess Medical Center, Boston, MA, and Children’s Hospital Boston, Boston, MA, USA.
Participants

Inclusion criteria: pregnant women with prepregnancy or 1st trimester BMI equal to or greater than 25 kg/m² and less than 45 kg/m², singleton pregnancy, willing to consume the diets for duration of pregnancy, participant to be at week 28 or less of pregnancy at baseline visit.

Exclusion criteria: smoking during pregnancy, major medical illness (e.g., diabetes mellitus, hypertension, thyroid disease), taking prescription medication known to affect body weight, alcohol consumption during pregnancy, intention to deliver infants in the environment outside of Beth Israel Deaconess MedicalCenter, Boston, high level of physical activity.

Interventions

Intervention group 1: nutrition education, dietary counselling, and a low-GL diet.

Intervention group 2: nutrition education, dietary counselling, and a low-fat diet.

Outcomes

Maternal outcome: weight change

Infant outcome: macrosomia, large-for-gestational age, caesarean delivery.

Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskRandomly “permuted blocks of 2 and 4 preventing anticipation of future assignments.
Allocation concealment (selection bias)Low riskSeparate random assignment envelopes for each stratum. Random assignment envelopes were prepared by the hospital clinical trials unit.
Blinding (performance bias and detection bias)
All outcomes
Low riskThe following staff were blinded to group assignment: obstetricians who provided clinical care to subjects; nurses who measured maternal body weight and blood pressure, collected and processed maternal blood samples, and analysed urinalyses; labour and delivery room nurses who obtained birthweight; laboratory staff who analysed maternal blood; and staff who performed data entry. Staff who performed maternal body composition analysis, 24-h dietary recalls, and infant anthropometric measurements “were predominantly, but not always”, blinded due to logistical considerations. Formal blinding of subjects was not possible, although subjects were not informed of their group assignments.
Incomplete outcome data (attrition bias)
All outcomes
Unclear risk46 women were randomised and infant outcomes were available for 45. There was some loss to follow-up among women with outcome data at 36 weeks available for 38. Reasons for loss were explained and loss was reasonably balanced across groups. It was stated that analysis was by randomisation group irrespective of whether or not women received the intended intervention.
Selective reporting (reporting bias)Unclear riskAssessment from published study report.
Other biasLow riskBaseline characteristics of subjects did not differ between intervention groups.

Santos 2005

MethodsRandomised clinical trial, set in a referral centre prenatal clinic in Porto Alegre, Brazil, during the period 2000–2002.
Participants

Inclusion criteria: healthy, nonsmoking pregnant women, aged 20 years or more, of gestational age less than 20 weeks, having a BMI between 26 and 31 kg/m² (corresponding to a prepregnancy BMI of 25-30 kg/m²) (overweight), and without diabetes or hypertension.

Exclusion criteria: not stated.

Interventions

Intervention (n = 37): the intervention consisted of a program of supervised physical exercise of 60 minutes duration, performed 3 times per week for 12 weeks. Each session consisted of 5-10 minutes of warm up, 30 minutes of heart rate-monitored aerobic activity, 10-15 minutes of exercise involving upper and lower limbs, and 10 minutes of stretching and relaxation. Aerobic activities were always performed between 50% and 60% of the maximum predicted heart rate, never exceeding 140 beats per minute. The exercises followed the recommendations concerning physical activity practice during pregnancy according to the American College of Sports Medicine, and the American College of Obstetricians and Gynecologists.

Control (n = 35): the control group participated in once-weekly sessions that included relaxation (respiratory exercises and light stretching but no aerobic or weight-resistance exercises) and focus group discussions concerning maternity. Control participants were neither encouraged to exercise nor discouraged from exercising.

Outcomes

Weight gain, low birthweight, prematurity.

Weight gain was calculated from different between weight at baseline and weight after 12 weeks of intervention.

Notes

At baseline; age (exercise, control) 26.0 ± 3.4, 28.6 ± 5.9 years.

BMI (exercise, control) 28.0 ± 2.1, 27.5 ± 2.1 kg/m².

Gestational age (exercise, control) 17.5 ± 3.3, 18.4 ± 3.9 weeks.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskWomen were randomised following a blocked sequence generated from a random number table by a statistician not participating in other aspects of the study.
Allocation concealment (selection bias)Low riskThe study coordinator implemented the randomisation by using numbered, opaque envelopes.
Blinding (performance bias and detection bias)
All outcomes
Low risk

The intervention consisted of an unblinded program of supervised physical exercise.

The same cardiologist, blinded to treatment allocation, performed both tests.

The anaerobic threshold was determined by review of the gas exchange curves by 2 cardiologists working independently and blinded to treatment allocation.

Incomplete outcome data (attrition bias)
All outcomes
High riskLoss to follow-up 22%, 19.6%, and 23.9% in intervention and control groups.                                                
Selective reporting (reporting bias)Unclear riskCould not determine.
Other biasHigh riskWomen in the intervention group were somewhat younger, had higher physical activity, and were earlier in their pregnancy.

Silverman 1971

MethodsRandomised controlled trial, set in private practice of 1 of the physicians, Los Angeles, California.
Participants

Pregnant women who were either overweight or gaining weight at an excessive rate. Patients from upper middle class or high social economic groups. There was no other basis for selection or exclusion of participants.

Average age 24.8 and 25.0 years.

Interventions

Intervention (n = 37): diethylpropion hydrochloride tablet, 75 mg.

Control (n = 38): placebo tablet.

OutcomesWeight change at each stage of gestation.
Notes

Age (intervention, control): 24.8, 25.0 years.

Average gestation age started medication (intervention, control): 28, 25 weeks.

BMI (intervention, control): 21.74, 22.45 kg/m².

No standard deviations for continuous outcomes were reported.

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskUsed a table of random numbers to assign the patients to active or placebo tablets.
Allocation concealment (selection bias)Unclear riskNo information provided.
Blinding (performance bias and detection bias)
All outcomes
Low riskDouble blind procedure.
Incomplete outcome data (attrition bias)
All outcomes
High riskThere was a vastly difference drop-out rate between the 2 groups, 10/38 in the intervention group and 28/37 in the control group.
Selective reporting (reporting bias)Unclear riskCould not determine.
Other biasLow riskThe pretreatment characteristics were similar.

Thornton 2009

MethodsRandomised controlled trial, set in the ambulatory obstetric clinics of 3 tertiary care medical centres - Morristown Memorial Hospital, St Luke’s-Roosevelt Hospital Center, and Jamaica Hospital Medical Center. Each study site was an urban, public clinic of a teaching hospital, New York Medical College.
Participants

Inclusion criteria: pregnant with a single fetus between 12 and 28 weeks of gestation that had a BMI greater than or equal to 30 kg/m².

Exclusion criteria: patients with pre-existing diabetes, hypertension, or chronic renal disease.

Interventions

Intervention (n = 116): monitored group; counselled in nutrition by a registered dietitian and given a more detailed dietary intake protocol. The nutrition program for the monitored patients followed dietary guidelines similar to those used in patients with the diagnosis of gestational diabetes. The women in this group were asked to record in a diary all of the foods and beverages eaten during each day.

Control (n = 116): unmonitored group; counselled in nutrition by a registered dietitian regarding conventional prenatal nutrition guidelines.

Outcomes

Weight gain, weight retention (calculated from the difference between weight at 6 weeks' postpartum and weight at baseline).

GDM, pre-eclampsia, gestational hypertension, haemorrhage/infection postpartum, preterm delivery (< 37 weeks), labour induction, caesarean delivery, macrosomal infant (> 4500 gm).

Weight gain was weight difference between the baseline(12-28 weeks) pregnancy weight and weight before delivery.

Notes

Age (intervention, control) 26.8, 27.3.

BMI (intervention, control) 37.41 ± 7.01, 38.22 ± 7.48 kg/m².

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskA random-number table was used to assign each consecutively numbered envelope to either the study or control group in blocks of 10.
Allocation concealment (selection bias)Low riskEnvelopes were prepared and sequentially numbered. A card indicating the assigned group was placed in the envelope, and the envelope was sealed.
Blinding (performance bias and detection bias)
All outcomes
Unclear riskCould not determine.
Incomplete outcome data (attrition bias)
All outcomes
Low riskThe intention-to-treat principle was performed. Loss to follow-up 9.7%.
Selective reporting (reporting bias)Unclear riskCould not determine.
Other biasLow riskDemographic data for the randomised groups were comparable.

Vitolo 2011

MethodsRandomised controlled trial (pilot study), set in primary care settings in Porto Alegre, Brazil.
Participants

Inclusion criteria: gestational age between 10 and 29 weeks; women attending the prenatal care unit of the health unit

Exclusion criteria: positive testing for HIV, previous diagnostic of diabetes, hypertension, anaemia or another condition that needed a special diet and age over 35 years.

Interventions

Intervention group: (159 women) weight and diet were assessed at recruitment. The aim of the intervention was to improve diet and encourage weight-appropriate weight gain in pregnancy. For low weight women, the priority was increasing the energetic density of the meals. For normal weight women, daily consumption of vegetables, greens, fruit and water were encouraged and women were advised to restrict consume of fat-rich foods and oil in cooking. For the overweight women, the intervals between meals were prioritised and women were encouraged to restrict their consumption of snacks. Women received a further interview 1 month later to reinforce messages.

Control group: (162 women) women did not receive any special intervention but were informed about their weight and nutritional status and advised to seek professional help if they were under- or over-weight. Their doctors were also provided with the results of the nutritional evaluation.

OutcomesWeight gain.
Notes 
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)High riskNo sequence generation in advance of randomisation. Women were randomised by means of a dark pouch with 2 equal sized cubes containing the term intervention in 1 and control in the other.
Allocation concealment (selection bias)High risk2 cubes were concealed in a dark pouch and 1 was removed at the point of randomisation which indicated allocation. (It is possible that this could be changed by the person carrying out randomisation.)
Blinding (performance bias and detection bias)
All outcomes
Unclear riskThe impact of lack of blinding on the outcomes measured (weight gain) is not clear.
Incomplete outcome data (attrition bias)
All outcomes
Low risk315 women accepted participation in the study.There were 307 women with anthropometric data collected in the last trimester.
Selective reporting (reporting bias)Unclear riskThe results relate to the number of women with excessive or low weight gain at different gestational ages.
Other biasUnclear riskRisk of bias assessment from translated notes.

Wolff 2008

  1. a

    BMI: body mass index
    CHO: carbohydrate
    GDM: gestational diabetes mellitus
    GI: glycaemic index
    HGI: high glycaemic index
    Hi-Lo: high-low exercise
    IOM: Institute of Medicine
    ITT: intention-to-treat
    LGI: low glycaemic index
    Lo-Hi: low-high exercise
    Mo-Mo: moderate-moderate exercise
    n: number
    OGTT: oral glucose tolerance test
    RDA: recommended dietary allowance

MethodsRandomised controlled trial, set in Copenhagen, Denmark.
Participants

Inclusion criteria: pregnant obese women (BMI > 30 kg/m²), nondiabetic non-smoking and Caucasian recruited at 15 ± 3 weeks of gestation. 

Exclusion criteria: smoking, age < 18 or > 45, multiple pregnancy, or medical complication.

Interventions

Intervention (n = 23): restriction of gestational weight gain to 6-7 kg by 10 consultation of 1-hour each with trained dietitian. The women were instructed to eat a healthy diet according to the official Danish dietary recommendations (% fat, protein, CHO, 30, 15-20, 50-55%). The energy intake was restricted based on individually estimated energy requirements and estimated energetic cost of fetal growth.

Control (n = 27): the control group had no consultations with the dietitian and had no restrictions on energy intake or gestational weight gain.

All participants followed the routine clinical schedule.

Outcomes

Weight gain, weight retention at 4 weeks postpartum, pre-eclampsias, caesarean delivery.

Weight gain was calculated as difference between self-reported prepregnancy weight and weight just before delivery.

Notes

Age (intervention, control) 28 ± 4, 30 ± 5 years.

Gestational age (intervention, control) 15 ± 2, 16 ± 3 weeks.

BMI at inclusion visit (intervention, control) 34.9 ± 4, 34.6 ± 3 kg/m².

Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskThe computerised randomisation took place after the women had given written informed consent.
Allocation concealment (selection bias)Unclear riskNo information provided.
Blinding (performance bias and detection bias)
All outcomes
Low riskThe physicians and midwives were blinded in regard to the treatment assignment, and women were asked not to reveal their allocation.
Incomplete outcome data (attrition bias)
All outcomes
High riskLoss to follow-up 24%: 17.8% in intervention group, 28.9% in control group.
Selective reporting (reporting bias)Unclear riskCould not determine.
Other biasLow riskBaseline characteristics were similar.

Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion
Breslow 1963Non-randomised controlled trial.
Campbell 2004Participants included pregnant and nonpregnant women.
Faucher 2008It was not clear that women in this study were pregnant (community weight loss intervention).
Gray-Donald 2000Non-randomised controlled trial.
Hausenblas 2008Participants included both pregnant and postpartum women.
Ismail 1990Not a relevant intervention.This study examined the use of cefoxitin (an antibiotic) for the prevention of post-cesarean-section infection.
Kinnunen 2007Non-randomised controlled trial.
Moses 2007Participants were postpartum women (a follow-up study of Moses 2006).
Olson 2004Non-randomised controlled trial.
Te Morenga 2011This study did not include pregnant women.
Walker 1966Non-randomised controlled trial.
Wisner 2006Participants were postpartum women.

Characteristics of studies awaiting assessment [ordered by study ID]

Leiferman 2011

MethodsRandomised controlled trial.
ParticipantsPregnant women of the My Baby My Move (MBMM) program.
InterventionsAn antenatal community-based physical activity intervention.
OutcomesMinutes per week of moderate-intensity physical activity.
Notes 

Mohebi 2009

MethodsQuasi-experimental randomised and controlled study.
Participants110 pregnant women referring to Gonabad’s health centres.
InterventionsNutrition education program on the recommended weight gain during pregnancy; Application of Health Belief Model.
OutcomesWeight gain during pregnancy.
Notes 

Characteristics of ongoing studies [ordered by study ID]

Althuizen 2006

Trial name or titleDesign of the New Life(style) study: a randomised controlled trial to optimise maternal weight gain during pregnancy.
MethodsRandomised controlled trial.
Participants

Location: The Netherlands.

The aim is to include 275 participants in the study.

Women are eligible for participation when they are:

1) expecting their 1st child;

2) able to read, write, and speak Dutch;

3) within their 1st 14 weeks of pregnancy.

Interventions

Intervention: the New Life(style) intervention program consists of 5 individual counselling modules together with a general information brochure.

Control: usual care.

Outcomes

Primary outcomes: body weight, BMI, and skinfold thickness.

Secondary outcomes: physical activity, nutrition and blood levels of factors that are associated with energy homeostasis.

Starting dateFebruary 2005.
Contact information

Ellen Althuizen; e.althuizen@vumc.nl

Department of Public and Occupational Health, EMGO-Institute, VU UniversityMedical Center, Amsterdam, The Netherlands.

NotesOnly protocol has been published. Ongoing for the full publication.

Brand-Miller 2010

Trial name or titleA pregnancy intervention to reduce postprandial glucose excursions in the primary prevention of paediatric obesity.
MethodsRandomised controlled trial.
Participants

Location: Australia.

Target number of participants: 1650.

Inclusion: healthy pregnant women at 12 to 16 weeks' gestation who agree to be randomised.

Exclusion:

1. women with pregestational diabetes;
2. multiple birth;
3. assisted reproduction;
4. special diet or referred to a dietitian for other reasons.

InterventionsA conventional healthy diet or a low glycaemic index diet from 12 to 16 weeks' gestation for the remainder of pregnancy.
Outcomes

Primary outcomes:

1. prevalence of large gestational age at birth (more than 90th centile);
2. prevalence of childhood obesity as determined by BMI.

Secondary outcomes:

1. prevalence of gestational diabetes;
2. ponderal index;
3. prevalence of small-for-gestational age.

Starting date01/01/2008.
Contact information

Prof Jennie Brand-Miller; j.brandmiller@mmb.usyd.edu.au

Human Nutrition Unit, University of Sydney, NSW 2006 Australia.

Notes 

Brand-Miller 2011

Trial name or titleA randomised, 2-arm parallel dietary intervention study to compare the effects of consuming a low glycaemic diet or wholegrain high fibre diet on infant birthweight and body composition, complications related to GDM and progression to GDM diagnosis in women at high-risk of GDM.
MethodsRandomised controlled trial.
Participants

Pregnant: between 14-20 weeks of gestation and 1 or more of the following GDM risk factors: 1. Age: > 30 years 2. Family history of type 2 diabetes- 1st-degree relatives with type 2 diabetes 3. Overweight or obese: Prepregnancy BMI > 30 (Kg/m²) 4. Past history of GDM or glucose intolerance 5. History of ‘large-for-gestational-age’ babies: Previous baby > 4 kg 6. Belonging to a high-risk ethnic group: Aboriginal or Torres Strait Islander, Polynesian, Middle Eastern, Indian and Asian. 7. Ability to read and understand participant information and consent form 8. Ability to comply with the scheduled visits and dietary advice.

Target sample size: 150.

Interventions

Intervention group: low GI diet, consisting of protein (15%–25%), fat (30%–35%) and carbohydrate (45%–50%) content and a low dietary GI less than 50. Carbohydrate choices for the low GI diet will include pasta, low GI rice, low GI breakfast cereals and breads. The intervention duration is from 20 weeks' gestation until birth. The intervention involves 5 consultations with an accredited practising dietitian (APD) at 20, 24, 28, 32 and 36 weeks of gestation. At weeks 20 and 36, the approximate duration of each dietary education session is 60 minutes. At weeks 24, 28 and 32, the approximate duration of each dietary education session is 30 minutes. Handouts and recipes will be provided, and the participants will have access to the research dietitian via phone throughout their participation period. Participants will receive a food basket at each of the 5 education sessions with the dietitian (at week 20, 24, 28, 32 and 36 weeks of gestation) containing foods that are low GI to improve their compliance and understanding of the advised food choices.

Control group: wholegrain high fibre diet, consisting of protein (15%–25%), fat (30%–35%) and carbohydrate (45%–50%) content and a GI of approximately 60 (average GI of a normal healthy diet). Carbohydrate choices for the wholegrain high fibre diet will include potatoes, brown rice, wholemeal breads and wholegrain breakfast cereals. The intervention duration is from 20 weeks' gestation until birth. The intervention involves 5 consultations with an accredited practising dietitian (APD) at 20, 24, 28, 32 and 36 weeks of gestation. At weeks 20 and 36, the approximate duration of each dietary education session is 60 minutes. At weeks 24, 28 and 32, the approximate duration of each dietary education session is 30 minutes. Handouts and recipes will be provided, and the participants will have access to the research dietitian via phone throughout their participation period. Participants will receive a food basket at each of the 5 education sessions with the dietitian (at week 20, 24, 28, 32 and 36 weeks of gestation) containing foods that are wholegrain high fibre to improve their compliance and understanding of the advised food choices.

Outcomes

Primary outcome: birthweight Z-score,

Secondary outcomes: detection of GDM, need for insulin use, ponderal index, infant body composition, fasting blood glucose level, maternal weight gain, pregnancy complications, dietary assessment, the FTO gene, inflammatory markers such as Interleukin 6 (IL-6), leptin and C-Reactive Protein (CRP)

Starting date30/09/2010
Contact information

Professor Jennie Brand-Miller, j.brandmiller@usyd.edu.au

Human Nutrition Unit, School of Molecular Bioscience, G08- Biochemistry Building, The University of Sydney NSW 2006

Notes 

Brownfoot 2011

Trial name or titleWeighing in Pregnancy.
MethodsRandomised controlled trial.
ParticipantsPregnant women attending for antenatal care at < 20 weeks' gestation 18-45 years. Excluded multiple gestation or medical or psychiatric illness. (Target sample size 650.)
InterventionsWeighing as part of each antenatal visit compared with routine care.
OutcomesWeight gain within IOM and WHO recommendations; medical complications of pregnancy (pre-eclampsia, hypertension, gestational diabetes); need for induction of labour; mode of delivery; postpartum complication; infant birthweight; macrosomia and complications relating to macrosomia.
Starting date1st January 2010.
Contact informationfiona.brownfoot@thewomens.org.au
Notes 

Chasan-Taber 2009

Trial name or titleA randomised controlled trial of prenatal physical activity to prevent gestational diabetes: design and methods.
Methods

Randomised controlled trial.

A blocked randomisation is used such that both treatment groups are assigned an equal number of times in each set of 4 sequentially enrolled subjects.

Participants

Location: Bay State Medical Center in western Massachusetts.

Target number of participants: 364.

Inclusion criteria: women are sedentary, with a diagnosis of GDM in a prior pregnancy defined according to American Diabetes Association (ADA) criteria

Exclusion criteria: age < 18 or > 40 years, history of diagnosis of diabetes outside of pregnancy, hypertension, heart disease or chronic renal disease, current medications that adversely influence glucose tolerance, > 16 weeks' gestation, contraindications to participating in moderate physical activity, inability to read English at a 6th grade level, self-reported participation in > 30 minutes of moderate-intensity or vigorous-intensity exercise on > 3 days/week, and non singleton pregnancy.

Interventions

Exercise intervention: person education on exercise followed by weekly, biweekly and monthly mail and telephone follow-up.

Health and wellness intervention: person education health and wellness followed by weekly and monthly mail and telephone follow-up.

OutcomesMaternal weight gain (change in weight from pregravid to delivery), birthweight, Apgar score, caesarean delivery, macrosomia (> 4000 gm) and large-for-gestational age, defined as newborn weight the 90th percentile for completed gestational weeks using cutoff points defined by Oken.
Starting dateApril 2010.
Contact information

Lisa Chasan-Taber; lct@schoolph.umass.edu

Megan Ward Harvey, meward@schoolph.umass.edu

Notes 

Dodd 2010a

Trial name or titleLimiting weight gain in overweight and obese women during pregnancy to improve health outcomes: a randomised trial.
MethodsRandomised controlled trial.
Participants

Location: Australia.

Target sample size: 2574.

Inclusion criteria: pregnant women with a singleton, live gestation between 10-20 weeks who are obese or overweight (defined as a BMI greater that 25kg/m²).

Exclusion criteria: women with multiple pregnancy, or type 1 or type 2 diabetes diagnosed prior to pregnancy. There is no age range criteria for this trial.

Interventions

Women will be randomised to the dietary and lifestyle advice group or the standard care group.

Dietary and lifestyle advice group will receive a comprehensive intervention to limit weight gain in pregnancy that includes a combination of dietary, exercise and behavioural strategies.

Standard care group will continue to receive their pregnancy care according to local hospital guidelines, which does not currently include routine provision of dietary, lifestyle and behavioural advice).

Outcomes

Primary outcome: infant large-for-gestational age at birth (defined as birthweight > 90th centile for gestational age).

Secondary outcomes: adverse outcomes for the infant including preterm birth, adverse outcomes for the women, maternal quality of life and emotional well being and costs of health care.

Starting date1/02/2008.
Contact information

Dr Jodie Dodd; jodie.dodd@adelaide.du.au

University of Adelaide, Obstetrics & Gynaecology Women's and Children's Hospital Level 1, Queen Victoria Building 72 King William Road North Adelaide SA 5006

Notes 

Downs 2011

Trial name or titleActive Moms (A randomised physical activity intervention for pregnant women).
MethodsRandomised controlled trial.
ParticipantsPregnant women (inclusion and exclusion criteria not described).
Interventions2 physical activity interventions and a control group. 1 group received a structured intervention with face to face physical activity education, motivational support and moderate physical activity on 2 days per week for 70mins with an instructor. The 2nd group (lifestyle support) received educational support via mailed materials and phone support. The control group received standard care.
OutcomesPerformance (physical activity).
Starting dateNot clear.
Contact informationdsd11@psu.edu
NotesStudy reported in brief abstract with preliminary findings.

Ferrara 2010

Trial name or titleDiet, exercise and breastfeeding intervention program for women with gestational diabetes (DEBI Trial).
MethodsRandomised, single blind (outcomes assessor), active control, parallel assignment, efficacy study.
Participants

Location: USA.

Inclusion criteria: diagnosis of GDM.

Exclusion criteria: ever diagnosed with diabetes when not pregnant, ever diagnosed with cardiovascular disease, ever diagnosed with lung disease, haemoglobin < 9.5 mg/dL, haematocrit less than 30%, SBP >= 140 or DBP >= 90 in the last month.

Diagnosis of thyroid disease in the last month.

Interventions

Intervention: experimental women receiving the behavioural: diet, exercise, and breastfeeding intervention.

Control: standard care.

Outcomes

Primary outcome: postpartum weight retention.

Secondary outcomes: postpartum levels of plasma insulin, markers of insulin resistance, adiponectin, dietary fat, physical activity, and breastfeeding duration.

Starting dateSeptember 2005.
Contact information

Assiamira Ferrara,

Kaiser Permanente Division of Research, California, United States, 94612

Notes

This study has been completed.

No publications provided yet. Ongoing for the publication.

Haakstad 2010

Trial name or titleEffect of regular exercise in prevention of excessive weight gain in pregnancy.
MethodsRandomised, single blind (investigator).
Participants

Location: Norway.

Target sample size: 105.

Inclusion criteria: primiparous women who have not participated in a structured exercise program, including significant amounts of walking for the past 6 months, ability to read, write and speak Norwegian, and to be within their 1st 24 weeks of pregnancy.

Exclusion criteria: severe heart disease, pregnancy-induced hypertension, history of more than 2 miscarriages, persistent bleeding after week 12 of gestation, poorly controlled thyroid disease, poorly controlled pre-eclampsia, and/or other diseases that could interfere with participation, live too far from the university to be able to attend weekly training groups.

Interventions

Intervention: supervised exercise for the prevention of high weight gain.

Each session starts with 5 minutes warm up, followed by 30 minutes of aerobic activity, including cool down. This is followed by 15 minutes of strength training of the upper and lower limbs, and special focus on the deep abdominal stabilisation muscles. The last 5 minutes contains stretching, relaxation and body awareness exercises. The exercise-program follows the ACOG exercise prescription, and all aerobic activities will be performed at moderate intensity (60%-70% of maximal heart rate), measured by ratings of perceived exertion at 11-14 (somewhat hard) on the 6-20 Borg's rating scale. Control: participants are neither encouraged nor discouraged from exercising.

Outcomes

Primary outcomes: overall weight gain during pregnancy and proportion of participants exceeding weight gain above IOM recommendations. (Time frame: week 36-38 of pregnancy.)

Secondary outcomes: pregnancy complications, relationship between oxygen consumption, heart rate and blood lactate concentration at submaximal work loads, infant birthweight, length of labour and complications during delivery. (Time frame: week 36-38 of gestation.)

Starting dateNovember 2007.
Contact information

Lene Haakstad; lene.haakstad@nih.no

Norwegian School of Sport Sciences

NotesSome results was published in the abstract (Haakstad 2009). Ongoing for the full publication.

Ko 2010

Trial name or titleEffect of physical activity on metabolic syndrome in pregnancy and fetal outcome.
MethodsRandomised controlled trial, single blind (investigator).
Participants

Location: United States, Washington.

Target number of participants: 100.

Inclusion criteria: pregnant women 18-45 years old receiving prenatal care at MAMC.

Exclusion criteria: women do not have a gallbladder, do not speak English, over 14 weeks pregnant at study entry, do not plan to deliver at MAMC, have medical contraindications, unwilling to participate in exercise intervention program, < 18 years of age, currently engaged in a regular vigorous exercise program.

Interventions

Intervention group will exercise 3 times per week at moderate-vigorous intensity for 45 minutes per session through their 36 week of pregnancy.

Control group women will continue their usual physical activity throughout pregnancy.

Outcomes

Primary outcome: central adiposity.

Secondary outcomes: leptin levels, glucose insulin, cholesterol, fetal adiposity, neonatal adiposity.

Starting dateOctober 2007.
Contact informationCynthia W Ko, University of Washington.
Notes 

McAuliffe 2010

Trial name or titleA randomised control trial of low glycaemic index carbohydrate diet versus no dietary intervention in the prevention of recurrence of macrosomia.
Methods

Randomised controlled trial.

Randomisation will be achieved using computer-generated allocations in a ratio of 1:1 contained in sealed opaque envelopes.

Participants

Location: the National Maternity Hospital, Dublin, Ireland.

Target number of participants: 700.

Inclusion: secundigravid women of reproductive age (greater than 18 years and less than 45 years) whose 1st baby was macrosomic (birthweight > 4000 gm) will be recruited at 1st booking visit from the antenatal clinic at the National Maternity Hospital.

Exclusion: diabetes, other medical disorders and those with poor previous pregnancy outcome.

Interventions

A diet arm: will be commenced on a low glycaemic index diet from 14 weeks' gestation to delivery under dietetic supervision.

A control arm: will receive no dietary intervention.

Outcomes

Primary outcomes: mean birthweight centiles and ponderal indices in each group. Outcomes will be measured at 14 weeks, 28 weeks, 34 weeks, at birth and 3 months postpartum.

Secondary outcomes: maternal weight gain in pregnancy; urinary metabolimics; cord insulin, leptin and IGF-1; placental weight, villous and vascular development.
Outcomes will be measured at 14 weeks, 28 weeks, 34 weeks, at birth and 3 months postpartum.

Starting dateAnticipated start date, 01/01/2007.
Contact information

Professor Fionnuala McAuliffe; fmcauliffe@nmh.ie

UCD Obstetrics & Gynaecology, UCD School of Medicine and Medical Science, University College Dublin, National Maternity Hospital, Holles Street.

Notes

Publication protocol in "Walsh J, Mahony R, Foley M, McAuliffe F. A randomised control trial of low glycaemic index carbohydrate diet versus no dietary intervention in the prevention of recurrence of macrosomia. BMC Pregnancy and Childbirth 2010;10:16.".

A pilot study of feasibility of the trial was published in the abstract of poster presentation of Mahony 2008.

Melo 2010

Trial name or titleEffects of physical exercise during pregnancy on the maternal and perinatal outcomes: a randomised clinical trial.
MethodsRandomised controlled trial.
Participants

Inclusion criteria: gestational age < 13 weeks, single pregnancy, alive fetus, no previous practice of physical activity.

Exclusion criteria: smoking, chronic maternal diseases, placenta praevia, history of preterm labour, bleeding.

Interventions

Intervention: 2 groups of exercise:

group 1: starting to practice physical exercise at 13 weeks; walking 3 times a week during 1 hour (moderate activity);

group 2: starting to practice physical exercise at 20 weeks; walking 3 times a week during 1 hour (moderate activity).

Control: without exercise practice.

Outcomes

Primary outcome measures: maternal outcomes: preterm labour, weight gain, pre-eclampsias, gestational diabetes. Perinatal outcome: birthweight, Apgar scores, body composition, admission at neonatal intensive care unit.

Secondary outcomes: Doppler flow velocimetry indexes: pulsatility, resistance and A/B relation (uterine arteries, fetal middle cerebral artery and umbilical arteries).

Starting dateApril, 2008.
Contact information

Adriana Melo; asomelo@gmail.com

Melania Amorim, PhD, melamorim@uol.com.br

Universidade Estadual da Paraiba, Campina Grande, Paraiba, Brazil, 58100-000

Notes 

Morkved 2010

Trial name or titleEffects of regular exercise during pregnancy.
MethodsRandomised, single blind (outcomes assessor).
Participants

Location: Norway.

Target sample size: 380.

Inclusion criteria: pregnant women who attend the routine ultrasound control at the 3 hospitals at 18 weeks of pregnancy are invited to participate in the study. Women are eligible for the trial if they are healthy, 18 years or more, with a singleton live fetus at the routine ultrasound scan and a normal pregnancy.

Exclusion criteria: pregnancy complications, high risk for preterm labour, pain during pelvic floor muscle contractions, ongoing urinary tract infection, or diseases that could interfere with participation (following recommendations ACOG 2003) . In addition, women who live too far from the hospitals to be able to attend weekly exercise groups will be excluded.

Interventions

Intervention: regular exercise 45-60 minutes minimum 3 times per week.

Control: standard care.

Outcomes

Primary outcomes: gestational diabetes/insulin resistance.

Secondary outcomes: fecal and urinary incontinence (incontinence scores)/lumbopelvic pain: pain intensity 100 mm visual analogue scale, disability rating index/labour.

Starting dateMay 2007.
Contact information

Siv Morkved; siv.morkved@ntnu.no

Department of Community Medicine and General Practice, Norwegian University of Science and Technology and Clinical Service, St Olavs Hospital, Trondheim University Hospital,

Trondheim, Norway, 7489

NotesNot recruiting participants.

Nagle 2011

Trial name or titleContinuity of midwifery care and gestational weight gain in obese women.
MethodsRandomised controlled trial.
Participants214 primiparous women attending 1 of the study hospitals for maternity care with a booking BMI >30 and less than 17 weeks' gestation. Exclusion criteria include inability to speak English, multiple pregnancy, vaginal bleeding or serious medical condition.
InterventionsContinuity of midwifery care compared with routine management.
OutcomesWeight gain; women's experience of care and satisfaction with care; psychological well being.
Starting dateNot clear.
Contact informationcate.nagle@deakin.edu.au
Notes 

Oostdam 2009

Trial name or titleDesign of fit for 2 study: the effects of an exercise program on insulin sensitivity and plasma glucose levels in pregnant women at high risk for gestational diabetes.
MethodsRandomised controlled trial.
Participants

Location: The Netherlands.

Target number of participants: 160.

Inclusion criteria: between 14 and 20 weeks of pregnancy, over 18 years of age, sufficiently fluent in Dutch, being able to be moderately physically active, and willingness to give written informed consent.

Exclusion criteria: diagnosed with (gestational) diabetes mellitus before randomisation, hypertension (systolic pressure > 160 mmHg and/or diastolic pressure > 100 mmHg), alcohol abuse (i.e. 2 glasses alcohol or more per day), drug abuse (except for incidental analgesic agents), use of the medication that affects insulin secretion or insulin sensitivity (antiviral, corticosteroids, antihypertensive drugs, all concomitant medication will be discussed), serious pulmonary (COPD, exercise-induced asthma), cardiac, hepatic or renal (serum creatinine < 150 mol/) impairment, malignant disease; serious mental or physical impairment i.e. preventing to understand or implement the study protocol/aim.

Interventions

Intervention group:  receives an exercise program twice a week in addition to usual care. The exercise program consist of aerobic and strength exercises and takes place under close supervision of a physiotherapist.

Control group:  receives usual care given by obstetricians and midwives. Dutch midwives and obstetricians follow closely the health status of each pregnant woman and their unborn child. The 1st appointment is usually between 9th and 12th week of gestation.

Outcomes

Primary maternal outcome measures are fasting plasma glucose and relative increase in insulin resistance. Primary neonatal outcome is birthweight.

Secondary outcome measures are maternal serum triglycerides, HDL, cholesterol and HbA1c, maternal weight gain during pregnancy, maternal physical activity level, foetal growth. Changes in direct healthcare and non-healthcare costs and indirect non-healthcare costs are studies as well.

Starting date14 November 2008.
Contact informationNicolette Oostdam; n.oostdam@vumc.nl
Notes 

Parat 2010

Trial name or titleImpact of education during pregnancy in overweight pregnant women (ETOIG).
MethodsRandomised controlled trial.
Masking: single blind (subject).
Participants

Location: Hospital Necker Paris, France.

Target number of participants: 800.

Inclusion criteria: pregnant women who agree the study, BMI > 25 kg/m² (BMI is based on retrospective self reported weight of the patient before pregnancy), no more than 21 weeks of gestation.

Exclusion criteria: younger than 18 years, multiple gestation, high-risk pregnancy, psychiatric pathology, diabetes diagnosed before the inclusion, fetal malformation, history of obesity surgery, no understanding of French language, planning to move to another area.

Interventions

Intervention: therapeutic education; intensive training individual and collective teaching.

Control: placebo comparator; classical follow-up with 2 individual consultations.

Outcomes

Primary outcomes:

-30% reduction of rapid infancy weight gain at 2 years defined as > + 0.67 change in weight SD score. The 0.67 SD represents the difference between the displayed centile lines on standard infant growth charts.

Secondary outcomes:

-reduction of rapid infancy weight gain between 0 and 6 months;

-reduction of the number of children with BMI over 19 at 2 years;

-reduction of incidence of gestational diabetes, pre-eclampsias, HTA during pregnancy, caesarean, fetal macrosomia;

-reduction of spontaneous feeding at 4 months;

-increase of breastfeeding (number of women and duration);

-reduction 1 and 2 years after pregnancy of mother weight and BMI (except 2nd pregnancy);

-reduction of abnormality of lipid and glycaemia test in women, 2 years after the pregnancy.

Starting dateSeptember 2008.
Contact information

Sophie Parat; sophie.parat@nck.aphp.fr

Raphael Serreau; raphael.serreau@cch.aphp.fr

Notes 

Poston 2010

Trial name or titleImproving pregnancy outcome in obese woman: a feasibility study.
MethodsFeasibility trial.
Participants

Location: United Kingdom.

Target number of participants: 100.

Inclusion: willing and able to give informed consent, pregnant women with booking BMI greater than or equal to 30 kg/m², singleton pregnancy.

Exclusion: pre-existing diabetes mellitus.

Interventions

The intervention consists of an individualised activity and diet plan. Women will be recruited between 10-16 weeks' gestation and the interventions will continue until delivery. Therefore maximum duration for any 1 woman would be 32 weeks (allowing for her to deliver at 2 weeks post-estimated date of delivery).

The control arm will have blood taken at recruitment and again in late pregnancy. Other than this they will receive usual pregnancy care and advice in accordance with local and national antenatal care guidelines.

Outcomes

Primary outcomes: improved maternal glucose sensitivity, assessed at recruitment (10-16 weeks), and again in the 3rd trimester (32-36 weeks).

Secondary outcomes: reduction in fetal, maternal and pregnancy complications, assessed at recruitment (10-16 weeks), and again in the 3rd trimester (32-36 weeks).

Starting date01/11/ 2008.
Contact information

Professor Lucilla Poston; Lucilla.poston@kcl.ac.uk

Maternal and Foetal Research Unit 10th Floor North Wing St Thomas Hospital, London

Tel: +44 (0) 20 7188 3639

Notes 

Shen 2010

Trial name or titleImpact of diet and exercise activity on pregnancy outcomes (IDEA).
MethodsRandomised, open label.
Participants

Location: Canada.

Inclusion criteria: age 18 years and older, pregnancy < 20 weeks, expressed interest in study and willingness to consent to participate in the study.

Exclusion criteria: obstetric or medical contraindications for exercise according to 2002 SOCG guideline (ruptured membranes, preterm labour, incompetent cervix, hypertensive disorders of pregnancy, growth restricted fetus, placenta previa, persistent bleeding in 2nd or 3rd trimester, significant metabolic, cardiovascular, respiratory or systemic disorder), pre-existing diabetes (except a history of GDM, but not in current pregnancy), multiple gestations.

InterventionsA community-based exercise and dietary intervention.
Outcomes

Primary outcomes: excessive weight gain during pregnancy.

Secondary outcomes: macrosomia, requirement of delivery procedures.

Starting dateJuly 2006.
Contact information

Garry Shen; gshen@ms.umanitoba.ca

University of Manitoba

Notes 

Smith 2010

Trial name or titleThe design of a community lifestyle programme to improve the physical and psychological well-being of pregnant women with a BMI of 30 kg/m² or more.
MethodsRandomised controlled trial.
Participants

Location: England.

Enrollment: 400 (200 from each area).

Inclusion criteria: women attending for antenatal care in a 2 UK hospitals with a BMI 30 kg/m² or greater.

Exclusion criteria: aged under 18, intend to move in the next 3 months, take weight control medication or if they have any cautions for starting exercise (this will be determined using the Revised Physical Activity Readiness Questionnaire (PARQ) and the Royal College of Obstetricians and Gynaecologists (RCOG) recommendations).

Interventions

The lifestyle programme will run for 1.5 hours per week for 10 weeks and is supplementary to standard antenatal care. Women will be invited to the 10-week programme at any stage before 30 weeks' gestation to ensure completion of the programme before their delivery.

The control group will receive routine care.

Outcomes

Primary outcomes: pregnancy weight gain, birthweight, mode of birth, and method of infant feeding at hospital discharge: psychological outcomes include self-efficacy, well-being, and goal attainment

Secondary outcomes: women's experience of pregnancy and healthcare services, amount of physical activity, food intake, and the suitability of the intervention components.

Starting dateOctober 2011 (recruitment).
Contact information

Professor Tina Lavender; tina.lavender@manchester.ac.uk

University of Manchester, Oxford Road, Manchester. M13 9PL

United Kingdom

Notes 

Vinter 2010

Trial name or titleLifestyle and pregnancy: the clinical effect of lifestyle intervention during pregnancy in obese women.
MethodsRandomised, open label, parallel assignment.
Participants

Location: Denmark.

Enrollment: 360.

Inclusion criteria: singleton pregnant, BMI ≥ 30 and ≤ 45 kg/m².

Exclusion criteria: chronic diseases, not Danish speaking, abuse of alcohol or drugs, preterm delivery in earlier pregnancies.

InterventionsLifestyle intervention: the intervention is composed of individual dietician counselling and physical training. The physical training includes weekly aerobic exercises in a fitness centre and lifestyle coaching in small groups.
Outcomes

Primary outcomes: caesarean section, GDM, hypertension/pre-eclampsias, large-for-gestational age and admission to neonatal intensive care unit. (Time frame: until 6 months postpartum.)

Secondary outcomes: metabolic markers. (Time frame: until 6 months postpartum.)

Starting dateOctober 2007.
Contact information

Christina A. Vinter; c.vinter@dadlnet.dk

Odense University Hospital

NotesThis study is not yet open for participant recruitment.

Weeks 2011

  1. a

    ACOG: the American Congress of Obstetricians and Gynecologists
    BMI: body mass index
    COPD: chronic obstructive pulmonary disease
    DBP: diastolic blood pressure
    FTO gene: fat mass and obesity-associated protein also known as alpha-ketoglutarate-dependent dioxygenase
    GDM: gestational diabetes mellitus
    HbA1c: haemoglobin A1c
    HDL: high density lipoprotein
    HIV: human immunodeficiency virus
    HTA: hydrothermal endometrial ablation
    IOM: Institute of Medicine
    MAMC: Madigan Army Medical Center
    OGTT: oral glucose tolerance test
    SBP: systolic blood pressure
    SD: standard deviation
    SOCG: the Society of Obstetricians and Gynaecologists of Canada
    WHO: World Health Organization

Trial name or titleEfficacy of Metformin in Pregnant Obese women - a randomised trial (EMPOWaR)
MethodsRandomised controlled trial.
ParticipantsWomen with BMI of 30 or more between 12-16 weeks' gestation.
InterventionsMetformin vs placebo.
OutcomesInfant birthweight, maternal insulin resistance, and other maternal and infant outcomes.
Starting dateNot clear.
Contact informationaweeks@liverpool.ac.uk
NotesPersonal communication (trial information sheet).

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