Caesarean section versus vaginal delivery for preterm birth in singletons

  • Review
  • Intervention

Authors

  • Zarko Alfirevic,

    Corresponding author
    1. The University of Liverpool, Department of Women's and Children's Health, Liverpool, UK
    • Zarko Alfirevic, Department of Women's and Children's Health, The University of Liverpool, First Floor, Liverpool Women's NHS Foundation Trust, Crown Street, Liverpool, L8 7SS, UK. zarko@liverpool.ac.uk.

    Search for more papers by this author
  • Stephen J Milan,

    1. St George's University of London, Population Health Sciences and Education, London, UK
    Search for more papers by this author
  • Stefania Livio

    1. University of Milan, Children's Hospital "V. Buzzi", Department of Obstetrics and Gynaecology, Milano, Italy
    Search for more papers by this author

Abstract

Background

Planned caesarean delivery for women thought be in preterm labour may be protective for baby, but could also be quite traumatic for both mother and baby. The optimal mode of delivery of preterm babies for both cephalic and breech presentation remains, therefore, controversial.

Objectives

To assess the effects of a policy of planned immediate caesarean delivery versus planned vaginal birth for women in preterm labour.

Search methods

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (5 August 2013).

Selection criteria

Randomised trials comparing a policy of planned immediate caesarean delivery versus planned vaginal delivery for preterm birth.

Data collection and analysis

Two review authors independently assessed trials for inclusion. Two review authors independently extracted data and assessed risk of bias. Data were checked for accuracy.

Main results

We included six studies (involving 122 women) but only four studies (involving only 116 women) contributed data to the analyses.

Infant

There were very little data of relevance to the three main (primary) outcomes considered in this review: There was no significant difference between planned immediate caesarean section and planned vaginal delivery with respect to birth injury to infant (risk ratio (RR) 0.56, 95%, confidence interval (CI) 0.05 to 5.62; one trial, 38 women) or birth asphyxia (RR 1.63, 95% CI 0.84 to 3.14; one trial, 12 women). The only cases of birth trauma were a laceration of the buttock in a baby who was delivered by caesarean section and mild bruising in another allocated to the group delivered vaginally.

The difference between the two groups with regard to perinatal deaths was not significant (0.29, 95% CI 0.07 to 1.14; three trials, 89 women) and there were no data specifically relating to neonatal admission to special care and/or intensive care unit.

There was also no difference between the caesarean or vaginal delivery groups in terms of markers of possible birth asphyxia (RR 1.63, 95% CI 0.84 to 3.14; one trial, 12 women) or Apgar score less than seven at five minutes (RR 0.83, 95% CI 0.43 to 1.60; four trials, 115 women) and no difference in attempts at breastfeeding (RR 1.40, 95% 0.11 to 17.45; one trial, 12 women). There was also no difference in neonatal fitting/seizures (RR 0.22, 95% CI 0.01 to 4.32; three trials, 77 women), hypoxic ischaemic encephalopathy (RR 4.00, 95% CI 0.20 to 82.01;one trial, 12 women) or respiratory distress syndrome (RR 0.55, 95% CI 0.27 to 1.10; three trials, 103 women). There were no data reported in the trials specifically relating to meconium aspiration. There was also no significant difference between the two groups for abnormal follow-up in childhood (RR 0.65, 95% CI 0.19 to 2.22; one trial, 38 women) or delivery less than seven days after entry (RR 0.95, 95% CI 0.73 to 1.24; two trials, 51 women).

Mother

There were no data reported on maternal admissions to intensive care. However, there were seven cases of major maternal postpartum complications in the group allocated to planned immediate caesarean section and none in the group randomised to vaginal delivery (RR 7.21, 95% CI 1.37 to 38.08; four trials, 116 women).

There were no data reported in the trials specifically relating to maternal satisfaction (postnatal). There was no significant difference between the two groups with regard to postpartum haemorrhage. A number of non-prespecified secondary outcomes were also considered in the analyses. There was a significant advantage for women in the vaginal delivery group with respect to maternal puerperal pyrexia (RR 2.98, 95% CI 1.18 to 7.53; three trials, 89 women) and other maternal infection (RR 2.63, 95% CI 1.02 to 6.78; three trials, 103 women), but no significant differences in wound infection (RR 1.16, 95% CI 0.18 to 7.70; three trials, 103 women), maternal stay more than 10 days (RR 1.27, 95% CI 0.35 to 4.65; three trials, 78 women) or the need for blood transfusion (results not estimable).

Authors' conclusions

There is not enough evidence to evaluate the use of a policy of planned immediate caesarean delivery for preterm babies. Further studies are needed in this area, but recruitment is proving difficult.

Résumé scientifique

Laccouchement par césarienne comparée à laccouchement par voie basse pour un accouchement prématuré dans les cas de grossesse unique

Contexte

L'accouchement par césarienne planifiée pour les femmes supposées être en travail prématuré pourrait avoir un effet protecteur pour le bébé, mais pourrait aussi être assez traumatisant à la fois pour la mère et le bébé. Le mode d'accouchement optimal pour les bébés prématurés, à la fois pour la présentation céphalique et la présentation par le siège, reste donc controversé.

Objectifs

Évaluer les effets d'une politique d'accouchement par césarienne planifiée demblée versus accouchement par voie basse planifié pour les femmes en travail prématuré.

Stratégie de recherche documentaire

Nous avons effectué des recherches dans le registre des essais cliniques du groupe Cochrane sur la grossesse et la naissance (5 août 2013).

Critères de sélection

Les essais randomisés comparant une politique d'accouchement par césarienne planifiée demblée versus accouchement par voie basse planifié pour les naissances prématurées.

Recueil et analyse des données

Deux auteurs de la revue ont indépendamment évalué les essais à inclure. Deux auteurs de la revue ont indépendamment extrait les données et évalué le risque de biais. L'exactitude des données a été vérifiée.

Résultats principaux

Nous avons inclus six études (portant sur 122 femmes), mais seules quatre études (impliquant seulement sur 116 femmes) ont fourni des données pour les analyses.

Infant

Il n'y avait très peu de données pertinentes pour les trois principaux critères de jugement pris en compte dans cette revue : Il n'y avait aucune différence significative entre une césarienne planifiée immédiate et l'accouchement par voie basse planifié pour la survenue de blessures de lenfant à la naissance (risque relatif (RR) 0,56, 95%, intervalle de confiance (IC) à 95 % 0,05 à 5,62 ; un essai, 38 femmes) ou dune asphyxie naissance (RR 1,63, IC à 95 % 0,84 à 3,14 ; un essai, 12 femmes). Les seuls cas de traumatisme à la naissance étaient une lacération de la fesse chez un bébé né par césarienne et de légères ecchymoses dans une autre assigné au groupe d'accouchement par voie basse.

La différence entre les deux groupes en ce qui concerne la mortalité périnatale n'était pas significative (0,29, IC à 95 % 0,07 à 1,14 ; trois essais, 89 femmes) et il n'y avait pas de données spécifiquement relatives à l'admission néonatale en soins spéciaux et/ou en unité de soins intensifs.

Il n'y avait également aucune différence entre le groupe accouchement par césarienne ou le groupe accouchement par voie basse en termes de marqueurs dune éventuelle asphyxie à la naissance (RR 1,63, IC à 95 % 0,84 à 3,14 ; un essai, 12 femmes) ou de score Apgar inférieur à sept à cinq minutes (RR 0,83, IC à 95 % 0,43 à 1,60 ; quatre essais, 115 femmes) et aucune différence dans les tentatives de l'allaitement maternel (RR 1,40, IC à 95 % entre 0,11 et 17.45 ; un essai, 12 femmes). Il n'y avait également aucune différence en ce qui concerne les convulsions/crises comitiales néonatales (RR 0,22, IC à 95 % 0,01 à 4,32 ; trois essais, 77 femmes), l'encéphalopathie hypoxique ischémique (RR 4,00, IC à 95 % 0,20 à 82,01 ; un essai, 12 femmes) ou le syndrome de détresse respiratoire (RR 0,55, IC à 95 % 0,27 à 1,10 ; trois essais, 103 femmes). Il n'y avait aucune donnée dans les essais portant spécifiquement sur l'inhalation méconiale. Il n'y avait également aucune différence significative entre les deux groupes pour un suivi anormal dans l'enfance (RR 0,65, IC à 95 % 0,19 à 2,22 ; un essai, 38 femmes) ou un accouchement moins de sept jours après l'entrée (RR 0,95, IC à 95 % 0,73 à 1,24 ; deux essais, 51 femmes).

Mother

Il n'y avait aucune donnée rapportée sur les admissions maternelles aux soins intensifs. Cependant, il n'y avait sept cas de complications majeures du post-partum dans le groupe affecté à une césarienne planifiée immédiate et aucun dans le groupe randomisé pour l'accouchement par voie basse (RR 7,21, IC à 95 % 1,37 à 38,08 ; quatre essais, 116 femmes).

Il n'y avait aucune donnée spécifique dans les essais relative à la satisfaction maternelle (postnatale). Il n'y avait aucune différence significative entre les deux groupes en ce qui concerne les hémorragies post-partum. Un certain nombre de critères de jugement secondaires non-prédéfinis ont également été pris en compte dans les analyses. Il n'y avait un avantage significatif pour les femmes dans le groupe d'accouchement vaginal par rapport à une fièvre puerpérale maternelle (RR 2,98, IC à 95 % 1,18 à 7.53 ; trois essais, 89 femmes) et d'autres d'infections maternelles (RR 2,63, IC à 95 % 1,02 à 6.78 ; trois essais, 103 femmes), mais aucune différence significative dans l'infection des plaies (RR 1,16, IC à 95 % 0,18 à 7,70 ; trois essais, 103 femmes), hospitalisation de la mère de plus de 10 jours (RR 1,27, IC à 95 % 0,35 à 4.65 ; trois essais, 78 femmes) ou le besoin de transfusion sanguine (résultats non estimables).

Conclusions des auteurs

Il n'existe pas suffisamment de preuves pour évaluer l'utilisation d'une politique d'accouchement par césarienne planifiée immédiate pour les bébés prématurés. Dautres études sont nécessaires dans ce domaine, mais le recrutement s'avère difficile.

Plain language summary

Caesarean section versus vaginal delivery for preterm birth for women with a single baby (not multiple birth)

There is not enough evidence to show the effects of a policy of planned immediate caesarean delivery rather than a policy of planned vaginal delivery for the birth of premature babies.

Caesarean section is an operation performed to deliver a baby through a cut in the abdomen and womb. Planned caesarean delivery for women thought to be in preterm labour may be protective for the baby, also preventing an intrapartum emergency surgery with its associated complications, but could also be traumatic for both the mother and her baby. More often than not, women thought to be in preterm labour deliver weeks later, often at term. There is, therefore, a real possibility that a policy of planned caesarean section may increase the number of babies born preterm.

We included six randomised studies (involving 122 pregnant women) but only four studies (involving 116 women) contributed to the analyses. Our review found that there is not enough reliable evidence to compare planned caesarean delivery with planned vaginal delivery. Sometimes a planned caesarean cannot happen because labour progresses too quickly and sometimes, even though vaginal delivery is planned, complications arising during labour may make a caesarean section necessary. The review found that not enough women have been recruited into trials and, therefore, the decision how best to deliver a preterm baby, either cephalic or breech presentation, remains opinion and current practice within a hospital, rather than being evidence-based.

All four trials were stopped early, due to difficulties with recruiting women. There were no data on serious maternal complications including admissions to intensive care unit. However, there were seven cases of major maternal postpartum complications in the group allocated to planned caesarean section (wound dehiscence, deep vein thrombosis, endotoxic shock and puerperal sepsis) and none in the group randomised to vaginal delivery. Excess blood loss from the birth canal after childbirth (postpartum haemorrhage) was not clearly different between the two groups, nor was birth asphyxia or respiratory distress syndrome or injury to the baby at birth.

Résumé simplifié

Laccouchement par césarienne comparée à laccouchement par voie basse pour un accouchement prématuré chez les femmes enceintes d'un bébé unique (pas de naissance multiple)

Il n'existe pas suffisamment de preuves pour montrer les effets d'une politique d'accouchement par césarienne planifiée immédiate plutôt qu'une politique d'accouchement par voie basse planifié pour la naissance de bébés prématurés.

La césarienne est une intervention permettant lextraction du bébé grâce à une incision dans l'abdomen et l'utérus. L'accouchement par césarienne planifiée pour les femmes supposées être en travail prématuré pourrait avoir un effet protecteur pour le bébé, et également prévenir une intervention chirurgicale d'urgence intrapartum, avec ses complications associées éventuelles, mais pourrait aussi être traumatisant à la fois pour la mère et son bébé. Le plus souvent, les femmes supposées être en travail prématuré accouchent plusieurs semaines plus tard, souvent à terme. Par conséquent, il existe une réelle possibilité qu'une politique de césarienne planifiée puisse augmenter le nombre de bébés nés prématurément.

Nous avons inclus six études randomisées (portant sur 122 femmes enceintes), mais seules quatre études (portant sur 116 femmes) ont été utilisées pour les analyses. Notre revue a trouvé qu'il n'existe pas suffisamment de preuves fiables pour comparer l'accouchement par césarienne planifié à l'accouchement par voie basse planifié. Parfois, une césarienne planifiée ne peut pas avoir lieu parce que le travail progresse trop vite et parfois, même si un accouchement par voie basse est prévu, les complications survenant pendant le travail peuvent rendre nécessaire une césarienne. La revue a constaté que trop peu de femmes ont été recrutées dans les essais et, par conséquent, la décision concernant la meilleure façon d'accoucher un bébé prématuré, par présentation céphalique ou par le siège, dépend de l'opinion et de la pratique usuelle au sein d'un hôpital, plutôt que d'être fondée sur des preuves.

Tous les quatre essais ont été arrêtés prématurément, en raison de difficultés avec le recrutement des femmes. Il n'y avait pas de données sur les complications maternelles graves, y compris les admissions en unité de soins intensifs. Cependant, il y avait sept cas de complications maternelles majeures du post-partum dans le groupe affecté à une césarienne planifiée (déhiscence de la plaie, thrombose veineuse profonde, choc endotoxinique et sepsis puerpéral) et aucun dans le groupe randomisé pour l'accouchement par voie basse. Il ny avait pas de différence significative évidente en ce qui concerne les pertes sanguines excessives de la filière pelvienne après l'accouchement (hémorragie du post-partum), la survenue d'asphyxie à la naissance, de syndrome de détresse respiratoire ou de blessure pour le bébé à la naissance, entre les deux groupes.

Notes de traduction

Traduit par: French Cochrane Centre 5th November, 2013
Traduction financée par: Ministère du Travail, de l'Emploi et de la Santé Français

Laički sažetak

Carski rez ili vaginalni porođaj za prijevremeni porođaj u žena koje nose jedno dijete

Nema dovoljno dokaza koji bi pokazali kakav je učinak planiranog carskog reza u odnosu na planirani vaginalni porođaj kad se radi o rađanju nedonoščadi.

Carski rez je kirurški zahvat kojem je cilj rađanje djeteta, a izvodi se pomoću reza na trbuhu i maternici. Smatra se da planirani carski rez može pomoći ženama za koje se smatra da imaju veći rizik od prijevremenog rođenja, te da to smanjuje i hitne kirurške zahvate tijekom rođenja zajedno s popratnim komplikacijama. Međutim, carski rez može također biti traumatičan za majku i dijete. Češće se događa da žene za koje se smatra da su pod rizikom od prijevremenog porođaja rode tjednima kasnije, često i na termin. Stoga postoji realna mogućnost da praksa planiranog carskog reza može povećati broj djece koja se rađaju prijevremeno.

U ovaj Cochrane sustavni pregled uključeno je 6 randomiziranih studija u kojima su sudjelovale ukupno 122 trudnice, ali samo 4 studije (s 116 žena) su dale podatke za statističku analizu. Sustavni pregled tih studija je utvrdio da nema dovoljno pouzdanih dokaza za usporedbu planiranog carskog reza s planiranim vaginalnim porođajem. Ponekad se carski rez planira zbog toga što porođaj napreduje previše brzo te ponekad, iako je planiran carski rez, dođe do komplikacija tijekom porođaja zbog čega je carski rez nužan. U ovom je sustavnom pregledu utvrđeno da je u dosadašnjim studijama na tu temu bilo uključeno premalo žena pa odluka o tome kako poroditi dijete pod rizikom od prijevremenog porođaja, bez obzira na to je li okrenuto na glavu ili na zadak, i dalje ostaje prepuštena osobnom mišljenju stručnjaka, i nije utemeljena na dokazima.

Sve četiri studije prekinute su ranije zbog problema s uključivanjem ispitanica u studiju. Nisu prikazani podatci o ozbiljnim komplikacijama u majke, uključujući liječenje u jedinici intenzivne skrbi. Međutim, zabilježeno je 7 slučaja poslijeporođajnih komplikacija kod majki u skupini kojoj je dodijeljen planirani carski rez (popuštanje šavova na rani, duboka venska tromboza, endotoksični šok i puerperalna sepsa), a niti jedna takva komplikacija u skupini koja je razvrstana u vaginalni porođaj. Nije bilo razlike u pretjeranom gubitku krvi nakon porođaja između dvije skupine, niti u manjku kisika u djeteta nakon porođaja niti razvoja problema s disanjem u djeteta nakon porođaja.

Bilješke prijevoda

Hrvatski Cochrane
Prevela: Livia Puljak
Ovaj sažetak preveden je u okviru volonterskog projekta prevođenja Cochrane sažetaka. Uključite se u projekt i pomozite nam u prevođenju brojnih preostalih Cochrane sažetaka koji su još uvijek dostupni samo na engleskom jeziku. Kontakt: cochrane_croatia@mefst.hr

Background

The optimal mode of delivery for women thought to be in preterm labour is controversial. Claims that planned preterm caesarean delivery reduces the chances of fetal or neonatal death and birth trauma have been met by counter claims that such a policy leads to risk of serious morbidity for both mother and baby.

Malloy 1991 found no evidence that caesarean section can be protective for preterm neonates, especially for very low birthweight infants (less than 1500 g). The same author published further evidence that, for intermediate or late low-risk preterm neonates (32 to 36 weeks), primary caesarean section may in fact increase risk of neonatal mortality and morbidity, such as pulmonary hypoplasia, necrotizing enterocolitis or sepsis (Malloy 2009).

Caesarean section is known to be associated with an increased risk of respiratory morbidity in neonates, because hormonal and physiological changes associated with labour are necessary for lung maturation in neonates (Cohen 1985; Hansen 2008). Gravenhorst 1993 on the other hand, found a trend towards reduced neonatal mortality rate in preterm (before 32 weeks) or very low weight (less than 1500 g) babies with breech presentation born by caesarean section compared with vaginal delivery. There is also a question to what extent the data from the Term Breech Trial (Hannah 2000) may be applicable to preterm births. The Term Breech Trial (Hannah 2000) showed a reduction in perinatal mortality from 13/1000 to 3/1000 (risk ratio (RR) 0.23, 95% confidence interval (CI) 0.07 to 0.81) and a reduction in serious neonatal morbidity from 3.8 to 1.4 per cent with planned caesarean section (RR 0.36, 95% CI 0.19 to 0.65). No differences were reported between the two groups regarding the health of the infant at three months follow-up (Hannah 2002, RR 1.00, 95% CI 0.82 to 1.23) and equal rates of death or neurodevelopmental delay (Hannah 2004, RR 1.09, 95% CI 0.52 to 2.30) were evidenced at follow-up two years after the trial.

In the Term Breech Trial (Hannah 2000) maternal complications were similar in both groups, but the data about possible excess maternal morbidity and mortality (or lack of it) for women who undergo planned caesarean section are quite complex. In the 2005 WHO global survey on maternal and perinatal health (Villar 2007), the risk for caesarean section compared to vaginal delivery was three to five times higher for maternal death, twice higher for hysterectomy, and again twice higher for being admitted to intensive care and hospital stay of more than seven days. Postnatal infection (pyrexia, endometritis, puerperal sepsis), thrombosis and pulmonary embolism, and excessive blood loss are indeed higher after caesarean section (DOH 1996; Petitti 1985). However, a lot of these complications may be a consequence of underlying causes that lead to the need for caesarean section, particularly when the procedure is carried out as an intrapartum emergency. Planned caesarean section may be, therefore, seen as a way of preventing an intrapartum emergency surgery and its associated complications.

Another problem, particularly for preterm caesarean sections, is that the lower segment (where the uterine incision is usually performed) may not have formed. Consequently, a vertical incision of the upper part of the uterus may be necessary. In this instance, more complications can occur, including heavier blood loss (Shah 1990), and the need to perform future deliveries by caesarean section, because of the lack of strength of the womb scar. Furthermore, caesarean section for first birth seems to be associated with an increased risk of placenta praevia and placental abruption in the second pregnancy (Yanq 2007).

The concept of planned caesarean section for preterm birth implies that it is possible to diagnose preterm birth accurately and perform caesarean section very early in labour or just before labour starts. This is clearly not the case as, more often than not, women thought to be in preterm labour deliver weeks later, often at term. There is, therefore, a real possibility that a policy of planned caesarean section may increase the number of babies born preterm.

The risk associated with excess preterm births may be reduced with corticosteroids given before delivery (Roberts 2006) and magnesium sulphate for neuroprotection (Crowther 2009).

This review aims to address the issue of best mode of delivery for preterm births in singleton pregnancy. The mode of delivery in multiple pregnancies is addressed in a separate Cochrane review (Stock 2012).

Objectives

To assess the effects of a policy of planned immediate caesarean delivery as opposed to aiming for vaginal birth for women thought to be in labour and at high risk of delivering a preterm baby.

Methods

Criteria for considering studies for this review

Types of studies

Any randomised trial which compared a policy of planned immediate caesarean delivery versus a policy aiming for vaginal birth for women at high risk of delivering a preterm baby. We did not include quasi-randomised controlled trials.

Types of participants

Women presenting or thought to be in preterm labour (less than 37 weeks), irrespective of fetal presentation.

Types of interventions

Comparison of two policies to deliver preterm baby once the labour starts, or a decision is made that baby needs to be delivered:

  1. aiming to deliver preterm baby by planned immediate caesarean delivery; or

  2. aiming to deliver baby vaginally irrespective of the presentation (cephalic, breech).

We acknowledge the ambiguity with the term "planned" caesarean section. A planned caesarean section normally means that it is scheduled before the onset of labour (NICE 2011). However, for the purposes of this review, we refer to the term "planned immediate caesarean section", meaning a caesarean section which is planned only after the labour has started. When a woman presents in preterm labour, the issue is whether to deliver immediately by caesarean section to prevent preterm vaginal birth, or to aim to deliver vaginally with recourse to caesarean section if problems develop (Penn 1996). Planned immediate caesarean section in the context of this review implies performing caesarean section as soon as the spontaneous preterm birth is thought to be inevitable. However, this decision to perform caesarean section may be delayed in order to give corticosteroids to the mother before birth of the baby.

Types of outcome measures

The outcome measures used in previous versions of this review have now changed to those listed below. In addition, a number of outcomes not pre-specified have been analysed in this review, as indicated.

Please refer to Differences between protocol and review to see outcomes previously used.

Primary outcomes
Infant
  • Birth injury to infant

  • Birth asphyxia (occurs when a baby does not receive enough oxygen before, during, or just after birth) as defined by the trialists

Mother
  • Mother requires admission to intensive care/major maternal postpartum complications (as defined by trialists)

Secondary outcomes
Infant
  • Perinatal death

  • Neonatal admission to special care and/or intensive care unit

  • Hypoxic ischaemic encephalopathy (a condition of injury to the brain)

  • Breastfeeding at discharge

  • Breastfeeding at three months

  • Cord pH below normal range

  • Abnormal follow-up in childhood

  • Neonatal fitting/seizures

  • Meconium aspiration (means the newborn inhales a mixture of meconium and amniotic fluid, either in the uterus or just after delivery)

  • Apgar score less than seven at five minutes

  • Respiratory distress syndrome

  • Delivery less than seven days after entry

  • Neonatal infection (proven) (outcome not prespecified)

  • Intracranial pathology (outcome not prespecified)

  • Intracranial haemorrhage (outcome not prespecified)

  • Other birth trauma (outcome not prespecified)

  • Head entrapment (outcome not prespecified)

  • Necrotising enterocolitis (outcome not prespecified)

  • Cord prolapse (outcome not prespecified)

  • Need for mechanical ventilation (outcome not prespecified)

  • Ventilation (days) (outcome not prespecified)

  • Supplemental oxygen (days) (outcome not prespecified)

  • Neonatal jaundice (outcome not prespecified)

Mother
  • Maternal satisfaction (postnatal)

  • Postpartum haemorrhage (excess blood loss from the birth canal after childbirth, as defined by trialists)

  • Maternal puerperal pyrexia (outcome not prespecified)

  • Maternal wound infection (outcome not prespecified)

  • Other maternal infection (outcome not prespecified)

  • Maternal stay more than 10 days (outcome not prespecified)

  • Need for blood transfusion (outcome not prespecified)

Search methods for identification of studies

Electronic searches

We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register by contacting the Trials Search Co-ordinator (5 August 2013). 

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, MEDLINE and EMBASE, 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 each assigned to a review topic (or topics). The Trials Search Co-ordinator searches the register for each review using the topic list rather than keywords. 

We did not apply any language restrictions.

Data collection and analysis

Selection of studies

Two review authors Stefania Livio (SL) and Stephen Milan (SM)) independently assessed for inclusion all the potential studies we identified as a result of the search strategy. There was agreement but had there been any disagreement this would have been resolved through discussion or, if required, we would have consulted our remaining review author (Zarko Alfirevic (ZA)). We also included data provided from the previous version of the review (Grant 2010).

Data extraction and management

We designed a form to extract data. For eligible studies, we re-extracted data on the additional outcomes included in this review. Two review authors (SL; SM) extracted the data using the agreed form. We resolved discrepancies through discussion or, if required, we consulted a third review author (ZA). We entered data into Review Manager software (RevMan 2012) and checked for accuracy. When information regarding any of the above was unclear, we attempted to contact authors of the original reports to provide further details.

Assessment of risk of bias in included studies

Two review authors (SL and SM) independently assessed risk of bias for each study using the criteria outlined in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). We resolved any disagreements by discussion.

(1) Random sequence generation (checking for possible selection bias)

We described for each included study the method used to generate the allocation sequence in sufficient detail to allow an assessment of whether it should produce comparable groups.

We assessed the method as:

  • low risk of bias (any truly random process, e.g. random number table; computer random number generator);

  • high risk of bias (any non-random process, e.g. odd or even date of birth; hospital or clinic record number);

  • unclear risk of bias.   

 (2) Allocation concealment (checking for possible selection bias)

We described for each included study the method used to conceal allocation to interventions prior to assignment and assessed whether intervention allocation could have been foreseen in advance of, or during recruitment, or changed after assignment.

We assessed the methods as:

  • low risk of bias (e.g. telephone or central randomisation; consecutively numbered sealed opaque envelopes);

  • high risk of bias (open random allocation; unsealed or non-opaque envelopes, alternation; date of birth);

  • unclear risk of bias.

(3.1) Blinding of participants and personnel (checking for possible performance bias)

We described for each included study the methods used, if any, to blind study participants and personnel from knowledge of which intervention a participant received. We judged that studies were at low risk of bias if they were blinded, or that the lack of blinding would be unlikely to affect results.

We assessed the methods as:

  • low, high or unclear risk of bias participants;

  • low, high or unclear risk of bias for personnel.

(3.2) Blinding of outcome assessment (checking for possible detection bias)

We described for each included study the methods used, if any, to blind outcome assessors from knowledge of which intervention a participant received. We assessed blinding separately for different outcomes or classes of outcomes.

We assessed the methods used to blind outcome assessment as:

  • low, high or unclear risk of bias.

(4) Incomplete outcome data (checking for possible attrition bias due to the amount, nature and handling of incomplete outcome data)

We described for each included study, and for each outcome or class of outcomes, the completeness of data including attrition and exclusions from the analysis, stating whether attrition and exclusions were reported and the numbers included in the analysis at each stage (compared with the total randomised participants), reasons for attrition or exclusion where reported, and whether missing data were balanced across groups or were related to outcomes. Where sufficient information was reported, or was supplied by the trial authors, missing data were included in the analyses.

We assessed the methods as:

  • low risk of bias (e.g. no missing outcome data; missing outcome data balanced across groups);

  • high risk of bias (e.g. numbers or reasons for missing data imbalanced across groups; ‘as treated” analysis done with substantial departure of intervention received from that assigned at randomisation);

  • unclear risk of bias.

(5) Selective reporting (checking for reporting bias)

We described for each included study how we investigated the possibility of selective outcome reporting bias and what we found.

We assessed the methods as:

  • low risk of bias (where it is clear that all of the study’s pre-specified outcomes and all expected outcomes of interest to the review have been reported);

  • high risk of bias (where not all the study’s pre-specified outcomes have been reported; one or more reported primary outcomes were not pre-specified; outcomes of interest are reported incompletely and so cannot be used; study fails to include results of a key outcome that would have been expected to have been reported);

  • unclear risk of bias.

(6) Other bias (checking for bias due to problems not covered by (1) to (5) above)

We described for each included study any important concerns we have about other possible sources of bias and assessed whether each study was free of other problems that could put it at risk of bias:

  • low risk of other bias;

  • high risk of other bias;

  • unclear whether there is risk of other bias.

(7) Overall risk of bias

We made explicit judgements about whether studies were at high risk of bias, according to the criteria given in the Handbook (Higgins 2011). With reference to (1) to (6) above, we considered the direction of the bias and whether it was likely to impact on the findings. 

Measures of treatment effect

Dichotomous data

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

Continuous data

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

Unit of analysis issues

Cluster-randomised trials

We planned to include cluster-randomised trials in the analyses along with individually-randomised trials if any had been identified.

In future updates, if cluster-randomised trials are identified, we will adjust their sample sizes using the methods described in the Handbook (Higgins 2011) using an estimate of the intracluster correlation co-efficient (ICC) derived from the trial (if possible), from a similar trial or from a study of a similar population. If we use ICCs from other sources, we will report this and conduct sensitivity analyses to investigate the effect of variation in the ICC. We plan to synthesise the relevant information from both cluster-randomised trials and individually-randomised trials. We will consider it reasonable to combine the results from both if there is little heterogeneity between the study designs and the interaction between the effect of intervention and the choice of randomisation unit is considered to be unlikely.

We also planned to acknowledge heterogeneity in the randomisation unit and perform a sensitivity analysis to investigate the effects of the randomisation unit.

Dealing with missing data

We planned to note levels of attrition if this had been an issue, exploring the impact of including studies with high levels of missing data in the overall assessment of treatment effect by using sensitivity analysis.

For all outcomes, analyses were performed, as far as possible, on an intention-to-treat basis, i.e. we attempted to include all participants randomised to each group in the analyses, and participants were analysed in the group to which they were allocated, regardless of whether or not they received the allocated intervention. The denominator for each outcome in each trial being the number randomised minus any participants whose outcomes are known to be missing.

Where data were clearly reported in terms of intervention received rather than on an intention-to-treat basis (Wallace 1984), and the intention-to-treat data were unavailable, the trial was omitted from the analyses (Analysis 1.2 and Analysis 1.16).

Assessment of heterogeneity

We assessed statistical heterogeneity in each meta-analysis using the T², I² and Chi² statistics. We regarded heterogeneity as substantial if I² was greater than 30% and either T² was greater than zero, or there was a low P value (less than 0.10) in the Chi² test for heterogeneity. 

Assessment of reporting biases

If there had been 10 or more studies in the meta-analysis, we would have investigated reporting biases (such as publication bias) using funnel plots. In such an event we planned to assess funnel plot asymmetry visually, and use formal tests for funnel plot asymmetry. For continuous outcomes we had planned to use the test proposed by Egger 1997, and for dichotomous outcomes we would have used the test proposed by Harbord 2006. If asymmetry had been detected in any of these tests or was suggested by a visual assessment, we would have performed exploratory analyses to investigate it.

Data synthesis

We carried out statistical analysis using the Review Manager software (RevMan 2012). We used fixed-effect meta-analysis for combining data where it was reasonable to assume that studies were estimating the same underlying treatment effect: i.e. where trials were examining the same intervention, and the trials’ populations and methods were judged sufficiently similar. If there had been clinical heterogeneity sufficient to expect that the underlying treatment effects differed between trials, or if substantial statistical heterogeneity was detected, we used random-effects meta-analysis to produce an overall summary if an average treatment effect across trials was considered clinically meaningful. The random-effects summary was treated as the average range of possible treatment effects.

Where we used random-effects analyses, the results were presented as the average treatment effect with 95% confidence intervals, and the estimates of  T² and I².

Subgroup analysis and investigation of heterogeneity

Where we identified substantial heterogeneity, we investigated it using subgroup analyses and sensitivity analyses. We considered whether an overall summary was meaningful, and if it was, we used a random-effects analysis to produce it.

We carried out the following subgroup analyses:

  1. fetal presentation breech;

  2. fetal presentation cephalic.

All outcomes were used in subgroup analysis. The data were combined to obtain total summary statistics from the two subgroups. We assessed subgroup differences by interaction tests available within RevMan (RevMan 2012).

Sensitivity analysis

We planned to conduct sensitivity analyses if there had been a clear risk of bias associated with the quality of some of the included trials.

Results

Description of studies

Six studies (involving 122 women) were considered as potentially eligible for inclusion (Lumley 1985; MacLennan 1986; Penn 1996; Viegas 1985; Wallace 1984; Zlatnik 1993) and two trials were excluded (Dietl 1987; McColgin 1990). See Characteristics of included studies, Characteristics of excluded studies.

It was noted in the previous version of this review (Grant 2010) that three included trials were restricted to cephalic presentations (Lumley 1985; MacLennan 1986; Wallace 1984) whereas the other three included trials were breech presentations (Penn 1996; Viegas 1985; Zlatnik 1993). In Grant 2010, data were included from MacLennan 1986 which had recruited only two women, who were both randomised to the same group (caesarean delivery). The data for those two women were added to the data for the four women recruited to a separate Australian trial (Lumley 1985) which also stopped at a very early stage having recruited only two women to the caesarean section group and two to the planned vaginal birth groups. In this version of the review, we decided not to include the data from Lumley 1985 and MacLennan 1986 because of the extreme paucity of data. We had intended to include the data from Lumley 1985, but this data were not available from the paper. The original data had been obtained by correspondence with the author and we did not have access to this.

Consequently, four trials (involving 116 women) contribute data to our analyses (Penn 1996; Viegas 1985; Wallace 1984; Zlatnik 1993).

Risk of bias in included studies

Please refer to Figure 1; Figure 2, for a summary of 'Risk of bias' assessments.

Figure 1.

Risk of bias graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.

Figure 2.

Risk of bias summary: review authors' judgements about each risk of bias item for each included study.

It was noted in Grant 2010 that 'the quality of the data in the review has been significantly improved by the extra information provided by the authors' and wherever possible we have retained the data from Penn 1996; Viegas 1985; Wallace 1984; Zlatnik 1993 as it was reported in Grant 2010. As was noted in Grant 2010 'analyses have been based on all women randomised with no known withdrawals after trial entry, other than for longer-term follow-up. It is not possible to 'blind' the policies being compared, and this should be taken into account when reviewing the data'.

Allocation

One of the six trials included in this review described adequate methods of randomisation (Zlatnik 1993), however, post-randomisation consent was used in Zlatnik 1993. The other trials (Lumley 1985; MacLennan 1986; Penn 1996; Viegas 1985; Wallace 1984) were reported as randomised although the method of allocation was not specified.

Allocation concealment was assessed as low risk of bias in three trials (MacLennan 1986; Penn 1996; Zlatnik 1993) and unclear in the remaining trials (Lumley 1985; Viegas 1985; Wallace 1984).

Blinding

It is not possible to blind the policies being compared. All studies were therefore assessed as high risk of bias for blinding of participants and personnel. Insufficient information was reported for a definitive evaluation of outcome assessment and so all studies were assessed as unclear risk of bias for blinding of outcome assessment.

Incomplete outcome data

Two trials were at high risk of bias for incomplete outcome (Lumley 1985; MacLennan 1986), both having extreme paucity of data due to poor recruitment and stopping early. The remaining trials were assessed as unclear risk of bias (Penn 1996; Viegas 1985; Wallace 1984; Zlatnik 1993).

Selective reporting

All trials were assessed as unclear risk of bias for selective outcome reporting (Lumley 1985; MacLennan 1986; Penn 1996; Viegas 1985; Wallace 1984; Zlatnik 1993).

Other potential sources of bias

All trials were assessed as unclear risk of bias for other potential sources of bias (Lumley 1985; MacLennan 1986; Penn 1996; Viegas 1985; Wallace 1984; Zlatnik 1993).

Effects of interventions

A total of only 116 women were recruited to the four trials contributing to the analyses reported in this review.

In the previous version of this review, data were included from a trial (MacLennan 1986) that had recruited only two women. Both women were randomised to the same group (caesarean delivery). The data for those two women were added to the data for the four women recruited to a separate Australian trial (Lumley 1985) which also stopped at a very early stage. In this version of the review because of the extreme paucity of data, and because the original data from these trials is not now available, these trials are not included in the analysis.

For the infant

Primary outcomes

There were very little data relating to the three main (primary) outcomes considered in this review. There was no significant difference between planned immediate caesarean section and planned vaginal delivery with respect to birth injury to infant (risk ratio (RR) 0.56, 95% confidence interval (CI) 0.05 to 5.62; one trial, 38 women, (Analysis 1.1)) or birth asphyxia (RR 1.63, 95% CI 0.84 to 3.14; one trial, 12 women, (Analysis 1.2 )). The only cases of birth trauma were a laceration of the buttock in a baby who was delivered electively by caesarean section (Viegas 1985) and mild bruising in another allocated to the expectant group and delivered vaginally (Penn 1996).

Secondary outcomes

The difference between the two groups with regard to perinatal deaths was not significant (RR 0.29, 95% CI 0.07 to 1.14; three trials, 89 women (Analysis 1.3)) and there were no data specifically relating to neonatal admission to special care and/or intensive care unit.

There was no difference between the caesarean or vaginal delivery groups in hypoxic ischaemic encephalopathy (a condition of injury to the brain) (RR 4.00, 95% CI 0.20 to 82.01; one trial, 12 women (Analysis 1.5)), in attempts at breastfeeding (RR 1.40, 95% CI 0.11 to 17.45; one trial, 12 women (Analysis 1.6)) or in terms of markers of possible birth asphyxia, i.e. cord pH being below the normal range (RR 9.00, 95% CI 0.56 to 143.89; two trials, 33 women (Analysis 1.7).

There was also no significant difference between the two groups for abnormal follow-up in childhood (RR 0.65, 95% CI 0.19 to 2.22; one trial, 38 women (Analysis 1.8)), in neonatal fitting/seizures (RR 0.22, 95% CI 0.01 to 4.32; three trials, 77 women (Analysis 1.9)), in low Apgar score at five minutes (RR 0.83, 95% CI 0.43 to 1.60; four trials, 115 women (Analysis 1.11)), respiratory distress syndrome (RR 0.55, 95% CI 0.27 to 1.10; three trials, 103 women (Analysis 1.12)) or delivery less than seven days after entry (average RR 0.95, 95% CI 0.73 to 1.24; two trials, 51 women; Heterogeneity: Tau² = 0.02; Chi² = 1.66, df = 1 (P = 0.20); I² = 40% (Analysis 1.13).

There were no data reported in the trials specifically relating to meconium aspiration (where the newborn inhales a mixture of meconium and amniotic fluid, either in the uterus or just after delivery).

Non prespecified secondary outcomes

We have also included a number of non-prespecified outcomes: cord prolapse (Analysis 1.20); need for mechanical ventilation (Analysis 1.21); ventilation (days) (Analysis 1.22); supplemental oxygen (days) (Analysis 1.23); neonatal jaundice (Analysis 1.24) - none of them showed important differences between the two groups.

For the mother

Primary outcomes

There were no data reported on maternal admissions admission to intensive care. However, there were significantly more cases of major maternal postpartum complications (wound dehiscence, deep vein thrombosis, endotoxic shock and puerperal sepsis) in the group allocated to planned immediate caesarean section compared with the group randomised to vaginal delivery (RR 7.21, 95% CI 1.37 to 38.08; four trials, 116 women, (Analysis 2.2)).

Secondary outcomes

The included studies did not report data on maternal satisfaction (postnatal) (Analysis 2.3).

There was no significant difference between the two groups with regard to postpartum haemorrhage (excess blood loss from the birth canal after childbirth) (RR 3.69, 95% CI 0.16 to 83.27; four trials, 105 women (Analysis 2.4)).

Non prespecified secondary outcomes

A number of non-prespecified secondary outcomes were also considered in the analyses. There was a significant advantage for women in the vaginal delivery group with respect to maternal puerperal pyrexia (RR 2.98, 95% CI 1.18 to 7.53; three trials, 89 women, (Analysis 2.5)) and other maternal infection (RR 2.63, 95% CI 1.02 to 6.78, three trials, 103 women, (Analysis 2.7)), although only just significant, P = 0.05), but no significant differences in wound infection (Analysis 2.6), maternal stay more than 10 days (Analysis 2.8) or the need for blood transfusion (Analysis 2.9).

In terms of compliance with allocated intervention, 20% (9/46) of women allocated to elective caesarean section were actually delivered vaginally, usually because the delivery was too rapid to allow a caesarean to be performed. Twenty-one per cent (9/43) of women allocated to vaginal delivery were delivered by caesarean section, usually because of fetal distress.

Subgroup Analyses

There was no clear evidence for subgroup differences between breech and cephalic presentations for the following outcomes examined: perinatal death (test for subgroup differences P = 0.91, I² = 0% (Analysis 1.3)); Apgar score less than seven at five minutes (test for subgroup differences P = 0.62, I² = 0% (Analysis 1.11)); neonatal infection (test for subgroup differences P = 0.51, I² = 0% (Analysis 1.14)); intracranial pathology (test for subgroup differences P = 0.38, I² = 0% (Analysis 1.15)); or neonatal jaundice (test for subgroup differences P = 0.91, I² = 0% (Analysis 1.24)).

Discussion

Summary of main results

Only 116 women were recruited to the four trials contributing to the analyses reported in this review. All four trials were stopped early, due to difficulties with recruitment. Therefore, any firm conclusions regarding the relative merits of planned immediate caesarean section versus planned vaginal delivery should not be drawn from this review in order to guide current clinical practice.

The need for more 'intention-to-treat' data from properly controlled trials is essential.

Overall completeness and applicability of evidence

Eighteen of 89 babies (20%) were not delivered by the planned mode (Penn 1996; Wallace 1984; Zlatnik 1993). This reflects rapid progress of preterm labour and results in vaginal birth despite caesarean section being planned. On the other hand, problems developing during labour may require caesarean section despite aiming for vaginal birth. Any attempt to perform 'on treatment' analysis should be resisted, as it introduces considerable bias. The bias is likely to favour vaginal birth as quick, appropriately monitored preterm births tend to be uncomplicated, particularly for the mother, whilst intrapartum emergency caesarean sections when vaginal births were planned are likely to be particular risky for both mother and baby.

It is also noteworthy that the infants who fared worst in Zlatnik's study (as judged by cord blood pH and perinatal death) were those whose mothers were delivered too rapidly to be recruited to the trial (Zlatnik 1993). The problem was not due to vaginal delivery, but undiagnosed labour which was therefore not monitored.

Quality of the evidence

All the included studies were randomised controlled trials. However, in Penn 1996; Viegas 1985; and Wallace 1984, details of random sequence generation are not reported. It is important to note that in the case of all four trials, data collection was stopped early.

Potential biases in the review process

Whilst a systematic process for including and excluding studies in this review was adhered to in relation to the prespecified criteria, the final selection of studies is of course open to interpretation or criticism. For further details, please see Characteristics of included studies; Characteristics of excluded studies.

Agreements and disagreements with other studies or reviews

No new trials have been published since the previous version of this review (Grant 2010). However, we have not included the data from two trials which were previously included (Lumley 1985; MacLennan 1986).

Authors' conclusions

Implications for practice

Given that very few women have been recruited to trials of planned immediate caesarean section versus planned vaginal delivery for preterm birth, and that the quality of the trials conducted is generally unclear, we recommend that firm conclusions regarding the relative merits of planned immediate caesarean section versus planned vaginal delivery should not be drawn from this evidence to guide practice for preterm births.

Implications for research

Failure to successfully recruit to all trials carried out thus far highlights the challenges with recruitment in this area. We hope that this review will contribute further to the equipoise that, surely, must exist. We are confident that, with adequate resources and growing recognition about how important it is to base clinical decisions on sound evidence, well designed randomised trials are possible.

Acknowledgements

We are most grateful for the contribution of Adrian Grant and Cathryn Glazener, authors on the previous versions of this review, and to Sonja Henderson, Frances Kellie, Lynn Hampson, Jill Hampson, Denise Atherton and Leanne Jones for their guidance and support.

As part of the pre-publication editorial process, the first version of this review was commented on by three peers (an editor and two referees who are external to the editorial team), members of the Pregnancy and Childbirth Group's international panel of consumers and the Group's Statistical Adviser (Alfirevic 2012).

The National Institute for Health Research (NIHR) is the largest single funder of the Cochrane Pregnancy and Childbirth Group. The views and opinions expressed therein are those of the authors and do not necessarily reflect those of the NIHR, NHS or the Department of Health.

Data and analyses

Download statistical data

Comparison 1. Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Birth injury to infant138Risk Ratio (M-H, Fixed, 95% CI)0.56 [0.05, 5.62]
1.1 Breech138Risk Ratio (M-H, Fixed, 95% CI)0.56 [0.05, 5.62]
1.2 Cephalic00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
2 Birth asphyxia112Risk Ratio (M-H, Fixed, 95% CI)1.63 [0.84, 3.14]
2.1 Breech112Risk Ratio (M-H, Fixed, 95% CI)1.63 [0.84, 3.14]
2.2 Cephalic00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
3 Perinatal death389Risk Ratio (M-H, Fixed, 95% CI)0.29 [0.07, 1.14]
3.1 Breech251Risk Ratio (M-H, Fixed, 95% CI)0.28 [0.05, 1.49]
3.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.33 [0.03, 3.29]
4 Neonatal admission to special care and/or intensive care unit00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
4.1 Breech00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
4.2 Cephalic00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
5 Hypoxic ischemic encephalopathy112Risk Ratio (M-H, Fixed, 95% CI)4.0 [0.20, 82.01]
5.1 Breech112Risk Ratio (M-H, Fixed, 95% CI)4.0 [0.20, 82.01]
5.2 Cephalic00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
6 Breastfeeding1 Risk Ratio (M-H, Fixed, 95% CI)Subtotals only
6.1 Breastfeeding not attempted112Risk Ratio (M-H, Fixed, 95% CI)1.40 [0.11, 17.45]
6.2 Not breastfeeding at discharge00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
7 Cord pH below normal range233Risk Ratio (M-H, Fixed, 95% CI)9.0 [0.56, 143.89]
7.1 Breech116Risk Ratio (M-H, Fixed, 95% CI)9.0 [0.56, 143.89]
7.2 Cephalic117Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
8 Abnormal follow-up in childhood138Risk Ratio (M-H, Fixed, 95% CI)0.65 [0.19, 2.22]
8.1 Breech00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
8.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.65 [0.19, 2.22]
9 Neonatal fitting/seizures377Risk Ratio (M-H, Fixed, 95% CI)0.22 [0.01, 4.32]
9.1 Breech377Risk Ratio (M-H, Fixed, 95% CI)0.22 [0.01, 4.32]
9.2 Cephalic00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
10 Meconium aspiration00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
10.1 Breech00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
10.2 Cephalic00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
11 Apgar score less than seven at five minutes4115Risk Ratio (M-H, Fixed, 95% CI)0.83 [0.43, 1.60]
11.1 Breech377Risk Ratio (M-H, Fixed, 95% CI)0.74 [0.34, 1.60]
11.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)1.09 [0.30, 3.89]
12 Respiratory distress syndrome3103Risk Ratio (M-H, Fixed, 95% CI)0.55 [0.27, 1.10]
12.1 Breech265Risk Ratio (M-H, Fixed, 95% CI)0.57 [0.25, 1.30]
12.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.49 [0.13, 1.88]
13 Delivery < 7 days after entry251Risk Ratio (M-H, Random, 95% CI)0.95 [0.73, 1.24]
13.1 Breech251Risk Ratio (M-H, Random, 95% CI)0.95 [0.73, 1.24]
13.2 Cephalic00Risk Ratio (M-H, Random, 95% CI)0.0 [0.0, 0.0]
14 Neonatal infection (proven) (outcome not prespecified)3103Risk Ratio (M-H, Random, 95% CI)0.76 [0.12, 4.66]
14.1 Breech265Risk Ratio (M-H, Random, 95% CI)1.10 [0.07, 17.74]
14.2 Cephalic138Risk Ratio (M-H, Random, 95% CI)0.33 [0.03, 3.29]
15 Intracranial pathology (outcome not prespecified)4110Risk Ratio (M-H, Fixed, 95% CI)0.92 [0.27, 3.14]
15.1 Breech372Risk Ratio (M-H, Fixed, 95% CI)0.58 [0.12, 2.86]
15.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)1.96 [0.22, 17.10]
16 Intracranial hemorrhage (outcome not prespecified)00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
16.1 Breech00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
16.2 Cephalic00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
17 Other birth trauma (outcome not prespecified)4118Risk Ratio (M-H, Fixed, 95% CI)1.16 [0.17, 8.13]
17.1 Breech380Risk Ratio (M-H, Fixed, 95% CI)1.16 [0.17, 8.13]
17.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
18 Head entrapment (outcome not prespecified)4116Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
18.1 Breech378Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
18.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
19 Necrotosing entercolitis (outcome not prespecified)112Risk Ratio (M-H, Fixed, 95% CI)6.67 [0.39, 114.78]
19.1 Breech112Risk Ratio (M-H, Fixed, 95% CI)6.67 [0.39, 114.78]
19.2 Cephalic00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
20 Cord prolapse (outcome not prespecified)4116Risk Ratio (M-H, Fixed, 95% CI)0.25 [0.03, 1.92]
20.1 Breech378Risk Ratio (M-H, Fixed, 95% CI)0.25 [0.03, 1.92]
20.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
21 Need for mechanical ventilation (outcome not prespecified)112Risk Ratio (M-H, Fixed, 95% CI)1.87 [0.71, 4.88]
21.1 Breech112Risk Ratio (M-H, Fixed, 95% CI)1.87 [0.71, 4.88]
21.2 Cephalic00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
22 Ventilation (days) (outcome not prespecified)112Mean Difference (IV, Fixed, 95% CI)18.26 [-19.90, 56.42]
22.1 Breech112Mean Difference (IV, Fixed, 95% CI)18.26 [-19.90, 56.42]
22.2 Cephalic00Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]
23 Supplemental oxygen (days) (outcome not prespecified)112Mean Difference (IV, Fixed, 95% CI)3.71 [-20.85, 28.27]
23.1 Breech112Mean Difference (IV, Fixed, 95% CI)3.71 [-20.85, 28.27]
23.2 Cephalic00Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]
24 Neonatal jaundice (outcome not prespecified)3103Risk Ratio (M-H, Fixed, 95% CI)0.92 [0.57, 1.48]
24.1 Breech265Risk Ratio (M-H, Fixed, 95% CI)0.89 [0.38, 2.08]
24.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.94 [0.55, 1.63]
Analysis 1.1.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 1 Birth injury to infant.

Analysis 1.2.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 2 Birth asphyxia.

Analysis 1.3.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 3 Perinatal death.

Analysis 1.5.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 5 Hypoxic ischemic encephalopathy.

Analysis 1.6.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 6 Breastfeeding.

Analysis 1.7.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 7 Cord pH below normal range.

Analysis 1.8.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 8 Abnormal follow-up in childhood.

Analysis 1.9.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 9 Neonatal fitting/seizures.

Analysis 1.11.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 11 Apgar score less than seven at five minutes.

Analysis 1.12.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 12 Respiratory distress syndrome.

Analysis 1.13.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 13 Delivery < 7 days after entry.

Analysis 1.14.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 14 Neonatal infection (proven) (outcome not prespecified).

Analysis 1.15.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 15 Intracranial pathology (outcome not prespecified).

Analysis 1.17.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 17 Other birth trauma (outcome not prespecified).

Analysis 1.18.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 18 Head entrapment (outcome not prespecified).

Analysis 1.19.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 19 Necrotosing entercolitis (outcome not prespecified).

Analysis 1.20.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 20 Cord prolapse (outcome not prespecified).

Analysis 1.21.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 21 Need for mechanical ventilation (outcome not prespecified).

Analysis 1.22.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 22 Ventilation (days) (outcome not prespecified).

Analysis 1.23.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 23 Supplemental oxygen (days) (outcome not prespecified).

Analysis 1.24.

Comparison 1 Planned immediate caesarean section versus planned vaginal delivery in singletons (infant outcomes), Outcome 24 Neonatal jaundice (outcome not prespecified).

Comparison 2. Planned immediate caesarean section versus planned vaginal delivery in singletons (maternal outcomes)other)
Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size
1 Mother requires admission to intensive care00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
1.1 Breech00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
1.2 Cephalic00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
2 Major maternal postpartum complications4116Risk Ratio (M-H, Fixed, 95% CI)7.21 [1.37, 38.08]
2.1 Breech378Risk Ratio (M-H, Fixed, 95% CI)7.21 [1.37, 38.08]
2.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
3 Maternal satisfaction (postnatal)00Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]
3.1 Breech00Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]
3.2 Cephalic00Mean Difference (IV, Fixed, 95% CI)0.0 [0.0, 0.0]
4 Postpartum haemorrhage4105Risk Ratio (M-H, Fixed, 95% CI)3.69 [0.16, 83.27]
4.1 Breech367Risk Ratio (M-H, Fixed, 95% CI)3.69 [0.16, 83.27]
4.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
5 Maternal puerperal pyrexia (outcome not prespecified)389Risk Ratio (M-H, Fixed, 95% CI)2.98 [1.18, 7.53]
5.1 Breech251Risk Ratio (M-H, Fixed, 95% CI)2.98 [1.18, 7.53]
5.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
6 Maternal wound infection (outcome not prespecified)3103Risk Ratio (M-H, Fixed, 95% CI)1.16 [0.18, 7.70]
6.1 Breech265Risk Ratio (M-H, Fixed, 95% CI)1.16 [0.18, 7.70]
6.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
7 Other maternal infection (outcome not prespecified)3103Risk Ratio (M-H, Fixed, 95% CI)2.63 [1.02, 6.78]
7.1 Breech265Risk Ratio (M-H, Fixed, 95% CI)2.63 [1.02, 6.78]
7.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
8 Maternal stay more than 10 days (outcome not prespecified)378Risk Ratio (M-H, Fixed, 95% CI)1.27 [0.35, 4.65]
8.1 Breech378Risk Ratio (M-H, Fixed, 95% CI)1.27 [0.35, 4.65]
8.2 Cephalic00Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
9 Need for blood transfusion (outcome not prespecified)251Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
9.1 Breech113Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
9.2 Cephalic138Risk Ratio (M-H, Fixed, 95% CI)0.0 [0.0, 0.0]
Analysis 2.2.

Comparison 2 Planned immediate caesarean section versus planned vaginal delivery in singletons (maternal outcomes)other), Outcome 2 Major maternal postpartum complications.

Analysis 2.4.

Comparison 2 Planned immediate caesarean section versus planned vaginal delivery in singletons (maternal outcomes)other), Outcome 4 Postpartum haemorrhage.

Analysis 2.5.

Comparison 2 Planned immediate caesarean section versus planned vaginal delivery in singletons (maternal outcomes)other), Outcome 5 Maternal puerperal pyrexia (outcome not prespecified).

Analysis 2.6.

Comparison 2 Planned immediate caesarean section versus planned vaginal delivery in singletons (maternal outcomes)other), Outcome 6 Maternal wound infection (outcome not prespecified).

Analysis 2.7.

Comparison 2 Planned immediate caesarean section versus planned vaginal delivery in singletons (maternal outcomes)other), Outcome 7 Other maternal infection (outcome not prespecified).

Analysis 2.8.

Comparison 2 Planned immediate caesarean section versus planned vaginal delivery in singletons (maternal outcomes)other), Outcome 8 Maternal stay more than 10 days (outcome not prespecified).

Analysis 2.9.

Comparison 2 Planned immediate caesarean section versus planned vaginal delivery in singletons (maternal outcomes)other), Outcome 9 Need for blood transfusion (outcome not prespecified).

What's new

DateEventDescription
28 August 2013New search has been performedSearch updated. No new trials identified.
28 August 2013New citation required but conclusions have not changedReview updated.

History

Protocol first published: Issue 1, 1995
Review first published: Issue 1, 1995

DateEventDescription
24 April 2012New search has been performed

Search updated. No new trials identified.

Data from two included studies (Lumley 1985; MacLennan 1986) are no longer included in the analyses because of the extreme paucity of data.

The background and methods sections have also been updated.

24 April 2012New citation required but conclusions have not changed

A new team of review authors prepared this update.

Change of title used in previous versions of this review from "Elective caesarean section versus expectant management for delivery of the small baby" to "Caesarean section versus vaginal delivery for preterm birth in singletons".

See Differences between protocol and review.

11 February 2009Review declared as stableIt is very unlikely that future RCTs on this topic will be mounted because of difficulties in recruitment.
27 January 2009New search has been performedSearch updated. No new trials identified.
18 February 2008AmendedConverted to new review format.
1 June 2006New search has been performedSearch updated. No new trials identified.
25 February 2004New search has been performedSearch updated. No new trials identified.
31 March 2001New search has been performedSearch updated. The review was updated with unpublished data from an included trial (Zlatnik 1993), and the background, results, discussion and conclusions substantially amended. The title was changed from 'Elective versus selective caesarean section for delivery of the small baby' to 'Elective caesarean section versus expectant management for delivery of the small baby'.
13 December 2000New citation required and conclusions have changedSubstantive amendment.
1 December 2000New search has been performedSearch updated. The review was updated by inclusion of data from one further trial (Penn 1996), resulting in amendments to all the text.

Contributions of authors

Stefania Livio wrote the Background and Stephen Milan completed the Methods and Results sections. Data extraction for new analyses, completion of risk of bias and characteristics of included studies sections was performed by Stefania Livio and Stephen Milan. Stephen Milan conducted the new analyses. Zarko Alfirevic, Stefania Livio and Stephen Milan wrote the discussion and authors' conclusions.

The 2013 update was approved by all authors.

Declarations of interest

None known.

Sources of support

Internal sources

  • The University of Liverpool, UK.

External sources

  • National Institute for Health Research, UK.

    NIHR Programme of centrally-managed pregnancy and childbirth systematic reviews of priority to the NHS and users of the NHS: 10/4001/02

Differences between protocol and review

Title

Change of title used in previous versions of this review from 'Elective caesarean section versus expectant management for delivery of the small baby' to 'Caesarean section versus vaginal delivery for preterm birth'.

Types of participants  

Change of text used in previous versions of this review from 'women presenting in labour and thought to be carrying a small or immature baby, irrespective of fetal presentation' to 'women presenting or thought to be preterm labour (< 37 weeks) irrespective of fetal presentation'.

Types of interventions  

Change of text used in previous versions of this review from 'a policy of elective caesarean delivery in comparison with expectant management with recourse to caesarean section if a clear clinical indication arose' to:

'Comparison of two policies to deliver preterm baby once the labour starts, or a decision is made that baby needs to be delivered:

  1. aiming to deliver preterm baby by planned immediate caesarean delivery; or

  2. aiming to deliver baby vaginally irrespective of the presentation (cephalic, breech).

We acknowledge the ambiguity with the term "planned" caesarean section. A planned caesarean section normally means that it is scheduled before the onset of labour (NICE 2011). However, for the purposes of this review, we refer to the term "planned immediate caesarean section", meaning a caesarean section which is planned only after the labour has started. When a woman presents in preterm labour, the issue is whether to deliver immediately by caesarean section to prevent preterm vaginal birth, or to aim to deliver vaginally with recourse to caesarean section if problems develop (Penn 1996). Planned immediate caesarean section in the context of this review implies performing caesarean section as soon as the spontaneous preterm birth is thought to be inevitable. However, this decision to perform caesarean section may be delayed in order to give corticosteroids to the mother before birth of the baby.'

Types of outcome measures

Change of outcomes used in previous versions of this review from:

One or more of a range of outcome measures assessing the effects of the policies on: length of pregnancy; complications in labour (for example, cord prolapse, head entrapment); neonatal condition at birth (for example, Apgar score, cord pH, need for intubation or mechanical ventilation, admission to special care facility); subsequent neonatal morbidity (for example, seizures, infection, jaundice, intracranial pathology, trauma); fetal or neonatal mortality; long-term follow-up in childhood; serious maternal morbidity or mortality (for example, postpartum haemorrhage, anaemia, need for blood transfusion, infection and prolonged hospital stay); and breastfeeding.

to:

Primary outcomes

Infant
  • Birth injury to infant

  • Birth asphyxia (occurs when a baby does not receive enough oxygen before, during, or just after birth) as defined by the trialists

Mother
  • Mother requires admission to intensive care/major maternal postpartum complications

Secondary outcomes

Infant
  • Perinatal death

  • Neonatal admission to special care and/or intensive care unit

  • Hypoxic ischaemic encephalopathy (a condition of injury to the brain)

  • Breastfeeding at discharge

  • Breastfeeding at three months

  • Cord pH below normal range

  • Abnormal follow-up in childhood

  • Neonatal fitting/seizures

  • Meconium aspiration (means the newborn inhales a mixture of meconium and amniotic fluid, either in the uterus or just after delivery)

  • Apgar score at five minutes

  • Respiratory distress syndrome

  • Delivery less than seven days after entry

  • Neonatal infection (proven) (outcome not prespecified)

  • Intracranial pathology (outcome not prespecified)

  • Intracranial haemorrhage (outcome not prespecified)

  • Other birth trauma (outcome not prespecified)

  • Head entrapment (outcome not prespecified)

  • Necrotising enterocolitis (outcome not prespecified)

  • Cord prolapse (outcome not prespecified)

  • Need for mechanical ventilation (outcome not prespecified)

  • Ventilation (days) (outcome not prespecified)

  • Supplemental oxygen (days) (outcome not prespecified)#

  • Neonatal jaundice (outcome not prespecified)

Mother
  • Maternal satisfaction* (postnatal)

  • Postpartum haemorrhage (excess blood loss from the birth canal after childbirth) NB Including need for transfusion

  • Maternal puerperal pyrexia (outcome not prespecified)

  • Maternal wound infection (outcome not prespecified)

  • Other maternal infection (outcome not prespecified)

  • Maternal stay more than 10 days (outcome not prespecified)

  • Need for blood transfusion (outcome not prespecified)

Characteristics of studies

Characteristics of included studies [ordered by study ID]

Lumley 1985

Methods"Randomised"; method not specified.
Participants

Inclusion: in labour; single fetus in cephalic or breech presentation between 26-31 weeks; no congenital abnormality at ultrasound examination; no other contraindication to caesarean or vaginal delivery; consent to participate.

Setting (period of recruitment): Queen Victoria Medical Centre, Melbourne, Australia (1980). Number of randomised participants: elective 2, selective 2.

InterventionsI: spontaneous birth vs II: CS as soon as labour starts.
Outcomes
  • Major maternal postpartum complications

  • Birth injury to infant

  • Birth asphyxia

  • Mode of birth: CS

  • Neonatal death

  • Neonatal admission to NICU

  • Postpartum haemorrhage

  • Hypoxic ischaemic encephalopathy

  • Breastfeeding at discharge

  • Breastfeeding at 3 months

  • Cord pH below normal range

  • Abnormal follow-up in childhood

  • Neonatal fitting

  • Meconium aspiration

  • Apgar score at 5 min

  • Maternal satisfaction

NotesTrial terminated after 5 months because of recruitment difficulties (only 4 women randomised).
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskDetails of random sequence generation not reported.
Allocation concealment (selection bias)Unclear riskDetails of allocation concealment not reported.
Blinding of participants and personnel (performance bias)
All outcomes
High riskNot blinded.
Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskInsufficient information reported for definitive evaluation of outcome assessment.
Incomplete outcome data (attrition bias)
All outcomes
High riskTrial stopped early.
Selective reporting (reporting bias)Unclear riskDetails of women who were not randomised included in trial report.
Other biasUnclear riskAfter the study had been running for 5 months, only 4 women had been randomised. However, the birth register indicated there had been 33 deliveries between 26 and 31 weeks. 16 women were withdrawn at the discretion of consultants.

MacLennan 1986

MethodsRandomised trial: randomisation by central telephone allocation.
ParticipantsInclusion: spontaneous preterm labour; cephalic (or breech) presentation between 24-32 weeks; no contraindication to caesarean or vaginal delivery.
Setting (period of recruitment): Queen Victoria Hospital, Adelaide, Australia (1987).
Number of randomised participants: 2.
InterventionsI: vaginal delivery vs II: elective caesarean section.
Outcomes
  • Major maternal postpartum complications

  • Birth injury to infant

  • Birth asphyxia

  • Mode of birth: I VD, II CS

  • Neonatal death

  • Neonatal admission to NICU

  • Postpartum haemorrhage

  • Hypoxic ischaemic encephalopathy

  • Breastfeeding at discharge

  • Breastfeeding at 3 months

  • Cord pH below normal range

  • Abnormal follow-up in childhood

  • Neonatal fitting

  • Meconium aspiration

  • Apgar score at 5 min

  • Maternal satisfaction

NotesTrial terminated because of recruitment difficulties. In both cases, the presentation was cephalic.
Unpublished data were provided by the principal investigator.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskDetails of random sequence generation not reported.
Allocation concealment (selection bias)Low riskCentral telephone allocation.
Blinding of participants and personnel (performance bias)
All outcomes
High riskNot blinded.
Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskInsufficient information reported for definitive evaluation of outcome assessment.
Incomplete outcome data (attrition bias)
All outcomes
High riskTrial stopped early.
Selective reporting (reporting bias)Unclear riskOnly 2 women randomised.
Other biasUnclear riskOnly 2 women had been randomised when the trial stopped.  The intended sample size as > 500. Recruitment to trial proved too difficult.

Penn 1996

MethodsMulticentre randomised controlled trial with telephone randomisation. Minimisation algorithm used to balance groups for gestational age, centre and rupture of membranes.
ParticipantsInclusion: women in spontaneous preterm labour between 26 and 32 completed weeks' gestation with singleton breech fetus; no clear indication for CS or vaginal delivery.
Exclusion: intrauterine death or congenital fetal malformation, clear indications for CS or vaginal delivery.
Setting: 26 centres in England (teaching and district general hospitals). Recruitment ended June 1991. Number of randomised participants: elective 5, selective 8.
InterventionsI: Vaginal delivery.
II: Caesarean delivery.
Outcomes
  • Major maternal postpartum complications

  • Birth injury to infant

  • Birth asphyxia I: 4/7, II: 5/5

  • Mode of birth I: 2/8 CS 6/8 VD, II: 1/5 VD, 4/5 CS

  • Neonatal death I: 1/8, II: 0/5

  • Neonatal admission to NICU

  • Postpartum haemorrhage

  • Hypoxic ischaemic encephalopathy I: 0/7, II: 1/5

  • Breastfeeding at discharge

  • Breastfeeding at 3 months

  • Cord pH below normal range

  • Abnormal follow-up in childhood

  • Neonatal fitting

  • Meconium aspiration

  • Apgar score at 5 min

  • Maternal satisfaction

NotesTrial terminated after 17 months because of low recruitment due to clinicians' reluctance to randomise eligible women.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskDetails of random sequence generation not reported.
Allocation concealment (selection bias)Low riskTelephone randomisation co-ordinated by the Clinical Trial Service in Oxford.  A minimisation algorithm was used to provide a balance between trial groups in terms of: gestational age, participating centre, and presence or absence of ruptured membranes at trial entry.
Blinding of participants and personnel (performance bias)
All outcomes
High riskNot blinded.
Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskInsufficient information reported for definitive evaluation of outcome assessment.
Incomplete outcome data (attrition bias)
All outcomes
Unclear riskIntention-to-treat analysis. Some limitations with incomplete outcome data.
Selective reporting (reporting bias)Unclear riskDetails of all 13 participants included in trial report.
Other biasUnclear riskLow recruitment levels. Trial terminated after 2 years preliminary work when only 13 women had been randomised in 6 hospitals (3 teaching hospitals and 3 district general hospitals).

Viegas 1985

MethodsRandom allocation; method not stated.
ParticipantsInclusion: single pregnancy; in established preterm labour in breech presentation between 28-36 weeks; no contraindication to caesarean or vaginal delivery; no congenital malformations; no severe pre-eclampsia or IUGR; consent to participate.
Setting (period of recruitment): 5 large delivery units in Singapore (1982-3).
Number of randomised participants: elective 12, selective 15.
InterventionsI: vaginal delivery vs II: elective caesarean delivery.
Outcomes
  • Major maternal postpartum complications

  • Birth injury to infant I: 1/41, II: 0/32

  • Birth asphyxia

  • Mode of birth

  • Neonatal death I: 7/41, II: 2/32

  • Neonatal admission to NICU

  • Postpartum haemorrhage

  • Hypoxic ischaemic encephalopathy

  • Breastfeeding at discharge

  • Breastfeeding at 3 months

  • Cord pH below normal range

  • Abnormal follow-up in childhood I: 2/41, II: 2/32

  • Neonatal fitting

  • Meconium aspiration

  • Apgar score at 5 min

  • Maternal satisfaction

NotesIndividual patient data supplied by the first author. The data for randomised women reanalyzed by 1 of the review authors on an 'intention-to-treat' basis.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskDetails of random sequence generation not reported.
Allocation concealment (selection bias)Unclear riskDetails of allocation concealment not reported.
Blinding of participants and personnel (performance bias)
All outcomes
High riskNot blinded.
Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskInsufficient information reported for definitive evaluation of outcome assessment.
Incomplete outcome data (attrition bias)
All outcomes
Unclear riskRandomised data not reported separately from descriptive study group.
Selective reporting (reporting bias)Unclear riskRandomised data not reported separately from descriptive study group.
Other biasUnclear riskThe RCT (N = 23) is reported with data from a descriptive study group (N = 50) and there is no separation between the two.  Therefore it is not possible to isolate the randomised controlled trial data.

Wallace 1984

MethodsRandomised trial; method not stated.
ParticipantsInclusion: established preterm labour in cephalic presentation between 26-33 weeks; single pregnancy; no contraindication to caesarean or vaginal delivery; no congenital anomalies.
Setting (period of recruitment): Los Angeles County/University of Southern California Medical Center (1981).
Number of randomised participants: elective 23, selective 15.
InterventionsI: vaginal delivery vs II: caesarean delivery.
Outcomes
  • Major maternal postpartum complications

  • Birth injury to infant

  • Birth asphyxia I: 2/9, II: 1/5

  • Mode of birth

  • Neonatal death I: 1/9, II: 1/5

  • Neonatal admission to NICU

  • Postpartum haemorrhage

  • Hypoxic ischaemic encephalopathy I: 2/9, II: 1/5

  • Breastfeeding at discharge

  • Breastfeeding at 3 months

  • Cord pH below normal range

  • Abnormal follow-up in childhood

  • Neonatal fitting

  • Meconium aspiration

  • Apgar score at 5 min

  • Maternal satisfaction

NotesTrial terminated after 6 months because the proportion (63%) of babies with birthweight > 1500 g was "unacceptably high".
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Unclear riskDetails of random sequence generation not reported.
Allocation concealment (selection bias)Unclear riskDetails of allocation concealment not reported.
Blinding of participants and personnel (performance bias)
All outcomes
High riskNot blinded.
Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskInsufficient information reported for definitive evaluation of outcome assessment.
Incomplete outcome data (attrition bias)
All outcomes
Unclear risk2 women excluded for malpresentation after randomisation. Vaginal delivery group includes 3 randomised to caesarean section who delivered vaginally prior to surgery. 
Selective reporting (reporting bias)Unclear riskData for 14 cases eligible for the < 1500 g group reported separately.
Other biasUnclear riskHigh frequency of infants with weight > 1500 g. 38 women participated in total of which only 14 were eligible for the <1500 g group. After enrolling 40 women study discontinued.  Trialists had planned to enrol 175 in each group.

Zlatnik 1993

  1. a

    CS: caesarean section
    IUGR: intrauterine growth restriction
    min: minutes
    NICU: neonatal intensive care unit
    vs: versus

MethodsRandomised trial with sealed envelope method and post randomisation consent.
ParticipantsInclusion: established preterm labour in breech presentation between 28-36 weeks; single fetus; delivery not imminent; no fetal abnormality on abdominal X-ray examination; no contraindication to caesarean or vaginal delivery; no tocolytics used in labour; consent to participate.
Setting (period of recruitment): University of Iowa Hospitals, USA (1978-83).
Number of randomised participants: elective 18, selective 20.
InterventionsI: vaginal delivery vs II: caesarean delivery.
Outcomes
  • Major maternal postpartum complications

  • Birth injury to infant I: 2/20, II: 1/18

  • Birth asphyxia

  • Mode of birth

  • Neonatal death I: 5/20, II: 1/18

  • Neonatal admission to NICU

  • Postpartum haemorrhage

  • Hypoxic ischaemic encephalopathy

  • Breastfeeding at discharge

  • Breastfeeding at 3 months

  • Cord pH below normal range

  • Abnormal follow-up in childhood

  • Neonatal fitting

  • Meconium aspiration

  • Apgar score at 5 min

  • Maternal satisfaction

NotesTrial terminated after 52 months because of recruitment difficulties.
Unpublished data were provided by the author.
Risk of bias
BiasAuthors' judgementSupport for judgement
Random sequence generation (selection bias)Low riskTable of random numbers.
Allocation concealment (selection bias)Low riskSealed envelopes.
Blinding of participants and personnel (performance bias)
All outcomes
High riskNot blinded.
Blinding of outcome assessment (detection bias)
All outcomes
Unclear riskInsufficient information reported for definitive evaluation of outcome assessment.
Incomplete outcome data (attrition bias)
All outcomes
Unclear riskIntention-to-treat analysis.
Selective reporting (reporting bias)Unclear riskNo apparent issues with selective reporting.
Other biasUnclear riskThere were no significant differences between 2 groups in: maternal age, length of gestation, parity, or estimated or actual birthweight. Accrual of participants proved too difficult and authors acknowledge the sample size was too small.

Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion
Dietl 1987No information or data available from the authors.
McColgin 1990No information or data available from the authors.

Ancillary