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Keywords:

  • Delivery;
  • intervention;
  • neonatal;
  • obesity;
  • pregnancy;
  • weight gain

Abstract

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Objective  To minimise obese women’s total weight gain during pregnancy to less than 7 kg and to investigate the delivery and neonatal outcome.

Design  A prospective case–control intervention study.

Setting  Antenatal care clinics in the southeast region of Sweden.

Population  One hundred fifty-five pregnant women in an index group and one hundred ninety-three women in a control group.

Methods  An intervention programme with weekly motivational talks and aqua aerobic classes for obese pregnant women.

Main outcome measures  Weight gain in kilograms, delivery and neonatal outcome.

Results  The index group had a significantly lower weight gain during pregnancy compared with the control group (P < 0.001). The women in the index group weighed less at the postnatal check-up compared with the weight registered in early pregnancy (P < 0.001). The percentage of women in the index group who gained less than 7 kg was greater than that of women in the control group who gained less than 7 kg (P= 0.003). The percentage of nulliparous women in this group was greater than that in the control group (P= 0.018). In addition, the women in the index group had a significantly lower body mass index at the postnatal check-up, compared with the control group (P < 0.001). There were no differences between the index group and the control group regarding birthweight, gestational age and mode of delivery.

Conclusion  The intervention programme was effective in controlling weight gain during pregnancy and did not affect delivery or neonatal outcome.


Introduction

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

Obesity is a growing global public health problem and is as prevalent among pregnant women as in the general population.1 It is well known that obese women have an increased risk for several complications during pregnancy and delivery; gestational hypertension, pre-eclampsia, gestational diabetes, stillbirth, shoulder dystocia, operative vaginal deliveries, caesarean deliveries and postpartum infections.2–5 There is also an increased risk for neonatal complications, such as malformations, macrosomia, large for gestational age, late fetal death and early neonatal death.2–4,6 As a result of the continuing obesity epidemic, the antenatal healthcare systems, obstetricians and midwives will be forced to deal with the problems and risks related to obesity.

Excessive gestational weight gain among obese women seems to further increase the risk for unwanted obstetric outcomes.6–9 Pronounced weight gain during pregnancy is also the most important risk factor for high weight retention after pregnancy.10,11 Moreover, women who have a high weight gain during their first pregnancy and retain it into the second one also gain and retain more weight during the next pregnancy and puerperium.12 Even a modest increase of body mass index (BMI) between the first and the second pregnancy can result in an adverse pregnancy outcome.13

It is possible that a controlled weight gain or even weight loss during pregnancy can reduce the obstetric risks in obese women, but it is unclear how to best manage this weight gain reduction.

The American Institute of Medicine (IOM) has stated recommendations for weight gain depending on pre-pregnancy BMI. For women with a pre-pregnancy BMI of >29 kg/m2, the recommended weight gain is at least 6.8 kg during pregnancy.14

Four recent studies have focused on preventing excessive gestational weight gain by providing normal and overweight women intervention consisting of educational and behavioural strategies.15–18 Gray-Donald et al.15 found in a prospective intervention study that the weight gain was similar for normal and overweight pregnant women in an index group compared with a control group. Polley et al.16 showed that the intervention significantly reduced the percentage of normal weight women who exceeded the IOM recommendations, while the intervention had an opposite effect or no effect at all on overweight women. Olson et al.17 managed to reduce the risk of excessive weight gain only in a low-income subgroup of normal and overweight women. Furthermore, Kinnunen et al.18 reported in a controlled trial that individual counselling on diet and physical activity during pregnancy did not affect the proportion of primiparas exceeding weight gain recommendations of IOM.

We hypothesised that a behavioural intervention programme providing obese women with weekly motivational talks and regular physical activity throughout the pregnancy would result in a reduced weight gain compared with a control group who received regular antenatal care.

The aim of this study was to minimise obese women’s total weight gain during pregnancy to less than 7 kg and to investigate the delivery and neonatal outcome.

Materials and methods

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

The Swedish antenatal healthcare system reaches almost 100% of all pregnant women. The antenatal and delivery care is free of charge. At the antenatal care clinics (ANCs), healthy pregnant women are advised to attend the regular antenatal programme with seven to nine visits to a midwife, and, if needed, extra appointments with an obstetrician and/or with the midwife. The first visit generally takes place around gestational weeks 10–12.19

Index group

All obese (BMI ≥ 30 kg/m2, n= 317) pregnant women consecutively registered between November 2003 and December 2005 at the ANCs in the city of Linköping and surrounding area were approached. The exclusion criteria: inability to understand Swedish, a pre-pregnant diagnosis of diabetes, thyroid dysfunction or a psychiatric disease treated with neuroleptic drugs excluded 45 women from participation. Thirteen women had an early miscarriage or a legal abortion and were also excluded, as well as 29 women who moved out of the catchment area in early pregnancy.

Two hundred and thirty obese women were thus eligible and invited to participate. Out of these, 70 women refrained from participation and 5 women dropped out during the intervention. A total of 155 obese women (67.4%) accepted and completed the intervention (Figure 1).

image

Figure 1. Flow chart representing women in the index and control groups.

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Control group

To constitute a control group, all obese, pregnant women (BMI ≥ 30 kg/m2, n= 437) consecutively registered during the same period at the ANCs in two nearby cities with surroundings were approached. The exclusion criteria were the same as for the index women and 42 women were excluded. Ten women had an early miscarriage or a legal abortion and were also excluded. Three hundred and eighty-five women were invited to participate; 177 women refrained from participation and 15 women dropped out during the study period. Finally, 193 women accepted and completed the participation (50.1%). The obese women in the control group attended the routine antenatal care programme (Figure 1).

The rate of obesity in the pregnant populations during the recruitment period was 8.4% in the city of Linköping and 7.3% in the two control cities. The women who refrained from participation in both groups were, on average, 1 year younger than those who participated in the study (29 versus 30 years, P= 0.018). Moreover, those who declined to participate had had previous children to a higher extent than those participating in the study (70.0% versus 54.9%, P < 0.001). They were also smokers to a greater extent (18.2% versus 7.8%, P < 0.001), and more likely to be unskilled workers or students (P= 0.032).

Intervention programme

The obesity intervention programme for pregnant women was based on a number of extra visits with a specially trained midwife. The cornerstone in the programme was a motivational interview/talk in early pregnancy,20 with the aim of motivating the obese pregnant woman to change her behaviour and to obtain information relevant to her needs. The midwife worked according to the following schedule:

  • • 
    Assessment of the pregnant woman’s knowledge of obesity as a risk factor for the pregnancy, birth and the child.
  • • 
    If the woman lacked sufficient knowledge, she was offered the information and given accurate facts.
  • • 
    The woman was also informed about the potential consequences of different behaviours associated with eating and food intake; written information was supplied if needed.
  • • 
    The woman was invited to a 30-minute individual session every week. The session included weight control and supportive talk.
  • • 
    All women who attended the programme were also invited to an aqua aerobic class (once or twice a week), especially designed for obese women.

All data related to pregnancy, delivery and the puerperium were registered in the standardised and identical Swedish antenatal pregnancy, delivery and neonatal records. The following data were collected: age, parity, marital status, occupation and smoking habits. Pregnancy, delivery and perinatal data were also obtained. The women’s weight was registered at the first visit to the ANC, during the pregnancy and at the postnatal check-up.

Statistics

All analyses were performed using the SPSS program, version 14.0 (SPSS Inc., Chicago, IL, USA). Statistical significance was defined as (two-sided) P≤ 0.05. Group differences were estimated by using the chi-square test on categorical variables and the Student’s t test (both paired and unpaired) on continuous, normally distributed variables. We also used analysis of covariance (ANCOVA) with the two weight gain variables (i.e. weight gain during pregnancy and weight gain between early pregnancy and at the postnatal check-up, respectively) as dependent variables. The covariate in the two models was age, group, parity, marital status, socio-economic group, occupation and smoking were included as independent factors.

The study was approved by the Human Research Ethics Committee, Faculty of Health Sciences, Linköping University.

Results

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

The socio-demographic variables and the distribution of BMI classes at the first ANC visit are shown in Table 1. There was a significant difference in socio-economic groups (P= 0.044). Weights registered at the ANC during pregnancy and postpartum are shown in Table 2.

Table 1.  Demographic data at the first ANC visit. All values are given as frequencies unless otherwise stated
 Index womenControl womenP
n%n%
  • *

    Student’s t test.

  • **

    χ2 test.

Age, mean (SD)*29.7 (4.48) 30.2 (4.92) 0.307
Parity** 0.285
No previous children6541.99247.7 
≥1 previous children9058.110152.3 
Marital status** 0.853
Married/cohabiting14593.517992.7 
Single mother42.673.6 
Other family situation63.973.6 
Smoking** 0.695
No14291.617992.7 
Yes138.4147.3 
BMI (kg/m2)** 0.948
30.0–34.910064.512765.8 
35.0–39.93623.24221.8 
>401912.32412.4 
Socio-economic group** 0.044
Unskilled workers3120.05025.9 
Skilled workers4529.06433.2 
Lower white collar workers74.5115.7 
Middle/high white collar workers and self-employed3925.22513.0 
Students1912.3178.8 
Unknown149.02613.5 
Occupation** 0.160
Gainfully employed10064.513671.6 
Not employed5535.55428.4 
Table 2.  Weight and weight gain during pregnancy and at postnatal check-up among the studied women*
 Index womenControl womenP**
nMeanSDnMeanSD
  • *

    Only women with simplex pregnancies are included.

  • **

    Student’s t test.

  • ***

    Registered weight in the same week as the delivery. If this value was missing, the weight was measured 1 or 2 weeks before the delivery.

  • ****

    That is ‘weight at the last check-up during pregnancy’–‘weight at the first ANC visit’.

  • *****

    That is ‘weight at postnatal check-up’–‘weight at the first ANC visit’.

  • ******

    χ2 test.

Weight at the first ANC visit15395.512.6519095.915.400.781
Weight at the last check-up during pregnancy***143103.613.31161106.014.430.131
Weight at the postnatal check-up; 10–12 weeks postpartum15093.213.3216396.514.480.037
Weight gain during pregnancy****1438.75.5116111.35.80<0.001
Weight gain between early pregnancy and at the postnatal check-up*****150−2.155.881620.755.34<0.001
Weight gain <7 kg during pregnancyn% n% 0.003******
51/14335.7 33/16120.5 

The index group had a lower weight gain during pregnancy compared with the control group (P < 0.001). The women in the index group had, in fact, lost weight at the postnatal check-up compared with the registered weight in early pregnancy (P < 0.001), while there was no significant difference in weight among the controls (P < 0.086).

Women who had a weight gain of less than 7 kg during the pregnancy were analysed separately. There were a significantly higher percentage of women in the index group than in the control group who gained less than 7 kg (P= 0.003) (Table 2). Further analyses showed that there were a greater percentage (32.2%) of nulliparous women in the index group than in the control group (15.2%) (P= 0.018).

The weight gains during pregnancy seemed to be independent of socio-demographic characteristics when analysed by means of ANCOVA (Table 3). After adjustment, the index women still had a lower weight gain during pregnancy (P= 0.001) and had lost more weight at the postnatal check-up (P < 0.001).

Table 3.  Weight gain during pregnancy among the studied women adjusted for socio-demographic characteristics*
 Index womenControl womenP*
MeanSDMeanSD
  • *

    ANCOVA (F test). Adjusted for age (covariate), parity (factor), marital status (factor), socio-economic group (factor), occupation (factor) and smoking (factor).

  • **

    P (age) = 0.022, P (parity) = 0.639, P (marital status) = 0.508, P (socio-economic group) = 0.562, P (occupation) = 0.164, P (smoking) = 0.003.

  • ***

    P (age) = 0.029, P (parity) = 0.034, P (marital status) = 0.238, P (socio-economic group) = 0.416, P (occupation) = 0.234, P (smoking) = 0.635.

Weight gain during pregnancy**7.5215.409.7816.240.001
Weight gain between early pregnancy and at the postnatal check-up***−3.3415.92−0.5216.23<0.001

Neonatal outcomes such as birthweight, gestational age and mode of delivery did not differ between the groups (Table 4). The same held true when the analyses were restricted to women who gained less than 7 kg during their pregnancies (data not shown).

Table 4.  Delivery and neonatal outcomes in the index and control groups
 Index groupControl groupP
n%n%
  • *

    Elective caesarean sections excluded.

  • **

    χ2 test.

  • ***

    Student’s t test.

Instrumental delivery*,** 0.961
Yes1410.0189.8 
No12690.016590.2 
Acute caesarean section*,** 0.698
Yes2014.32915.8 
No12085.715484.2 
Elective caesarean section** 0.106
Yes159.7105.2 
No14090.318394.8 
Birthweight (g)***, mean (SD)3688.0 (680.7)3678.9 (571.3)0.893
Gestational length (weeks)***, mean (SD)39.3 (2.11)39.3 (2.05)0.813

Discussion

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

This prospective case–control intervention study investigated the possibility to restrict weight gain during pregnancy among obese women by motivational talks and physical activity. The intervention resulted in a significantly lower weight gain during pregnancy and at the postnatal check-up among women in the index group compared with the control group. The women in the index group had furthermore a significantly lower BMI at the postnatal check-up compared with the control group. In addition, a greater percentage of first-time mothers in the index group gained less than 7 kg than those in the control group.

There were no differences between the groups regarding mode of delivery and neonatal outcome. The mean gestational age at delivery was the same in both groups, 39.3 pregnancy weeks. The women in the index group were invited to a 30-minute session every week. The session included discussion of weight control and supportive talk. This weekly individual support might have been an important factor in helping them to control weight gain. All women who attended the intervention programme were also invited to a specially designed aqua aerobic class (once or twice a week). In an earlier study,21 we asked the participants about their experiences with this kind of activity. The majority of the women stated that they were satisfied with this kind of physical exercise and that they also appreciated the social context, which gave them the chance to meet with other women who understood the significance of being obese. Consequently, in addition to providing the physical exercise itself, this activity might be an equally important social forum that can further inspire to weight control.

This type of intervention offers advantages and disadvantages. The Swedish Council on Technology Assessment in Health Care22 discusses the role of the therapist in behavioural therapy interventions for obese and states the importance of continuity. However, to meet with the same midwife for a long time period may on the other hand obstruct a progressive change in behaviour. Individual behavioural therapy is staff and time-consuming and is therefore both difficult and expensive to manage. Hence, most intervention studies among obese women are performed in groups.22

There were a significantly higher percentage of nulliparous women in the index group than in the control group who gained less than 7 kg. Possibly, a woman who expects her first child is more apt to give priority to a lifestyle change compared with a woman with one or more children, who simply recognises that she has less time to spend on herself than a woman having her first child. There might, therefore, be a need for a differentiated intervention programme specifically designed for obese pregnant women with previous children.

The percentage of women who refrained from participation in the study was much higher in the control group (41%) than in the index group (22%). This might be due to the fact that the index women were offered an intervention with extra support and aqua aerobic classes, whereas women in the control group did not receive any extra benefits. Five women in the intervention group and 15 women in the control group dropped out during the study. The reason for this was mainly that they felt that the visits were more frequent than they could handle.

Our results show a significantly lower weight gain during pregnancy and at the postnatal check-up among women in the intervention group. This is not in accordance with findings from other intervention studies with similar aims, which are still few. Gray-Donald et al.15 conducted a programme with, on average, four individual counselling sessions. They found no difference in weight gain between normal and overweight pregnant women in the intervention group compared with the controls. In a smaller Finnish intervention study primiparas from different BMI classes received individual counselling on diet and physical activity at five routine visits. This study was unable to prevent gestational weight gain exceeding the recommendations of IOM.18 Polley et al.16 showed that an intervention at regularly scheduled clinic visits significantly reduced the weight gain during pregnancy of normal weight women but had an opposite or no effect on overweight and obese women. The authors suggest that the findings may be due to a low rate of excessive weight gain in the control group of overweight and obese women or that the lack of efficacy may be due to recruitment from a lower income area, where few of the participants in the study were educated and over half were unemployed. In a study by Olson et al.17 similar results were observed. The intervention appeared to reduce the risk of excessive gestational weight gain only in the low-income subgroup of normal and overweight, but not obese, women. This is in contrast with our results where the intervention had an effect, irrespective of socio-demographic factors. Socio-economic status may be related to a person’s capability to assimilate and transform a message such that in the intervention programme. In our study, a greater percentage of women in the index group had a higher education compared with the control group, using standard classification of socio-economic groups. There were also a high proportion of gainfully employed women, both in the index and in the control group.

The intervention programme in our study differed from the concept followed in other studies in a significant way—namely the number of visits to the midwife. It is possible that frequent visits, in addition to our basic concept, facilitate weight gain control. One other important difference is the fact that the index group in the present study met with only one specialist midwife, which might have influenced the results. Another advantage of our study is that all women were weight measured at the ANC and that no self-reported weights have been used.

Neonatal outcome as birthweight have been investigated in intervention studies.15–18 Neither Gray-Donald et al.,15 Polley et al.16 nor Olson et al.17 found any difference in birthweight between the intervention and control groups. This is in accordance with our study.

One of the limitations with our study is that the sample sizes are smaller than, for obvious reasons, epidemiological studies, and therefore, we may not have been able to detect potential differences in pregnancy and neonatal outcome. Another limitation with the study is that the index and control groups were delivered at three different hospitals, which might have influenced the mode of delivery. A third and important limitation is the lack of randomisation. However, it is well known that a continuing intervention with a new treatment routine might influence the staff to change their behaviour and treatment regimens even to those women who are supposed to be controls and receive standard treatment. We therefore choose to use other cities and their ANCs as controls. In Sweden, the antenatal care programmes are very much standardised and almost identical concerning the treatment and supervision offered. Also, we were able to control for several background characteristics that otherwise could confound the results. However, some caution is advisable when generalising these results, as there were some differences in socio-demographic factors among women who participated in the study compared with those who declined to participate. In addition, the completion rates among the index women and the controls differed somewhat.

Weight loss intervention programmes that involve a combination of behaviour modifications, information, diet and exercise report a successful long-term maintenance of weight loss, but there is also some evidence that after a therapy stops, the individual returns to baseline weight.23–26 Whether the index women in this study will be able to maintain the change in attitude, eating habits, and thus weight control in a long-term perspective remains to be investigated.

In conclusion, this intervention programme was effective in controlling weight gain for obese women and especially nulliparous women during pregnancy and did not affect delivery or neonatal outcome.

Acknowledgements

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References

This study was supported by grants from The Research Fund of County Council in the South East Sweden, the Swedish Association of the Visually Impaired and the Swedish National Infant Foundation.

References

  1. Top of page
  2. Abstract
  3. Introduction
  4. Materials and methods
  5. Results
  6. Discussion
  7. Acknowledgements
  8. References
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