An updated review by the Cochrane Collaboration has looked at external cephalic version (ECV), a procedure used in an attempt to turn breech babies into a head-down position, and considered whether this has an effect on presentation at and method of delivery, and perinatal and maternal morbidity and mortality.
In the background to their review, the authors noted that:
- 3-4% of women who reach full term will have a baby in the breech position.
- Breech delivery has a higher incidence of poor perinatal outcomes than cephalic birth, and this is the case both for caesarean section and vaginal breech birth.
- Most women whose baby is in a breech presentation would prefer a vaginal birth (although they would have a caesarean section if this was medically indicated).
- Both methods of birth (vaginal birth and caesarean section) have been shown to be safe for the baby. Some studies show that caesarean section is safer for the baby than medically-managed breech vaginal delivery, though one analysis shows that vaginal breech birth is just as safe for the baby under certain conditions. Caesarean section does increase the risk of morbidity for the mother.
It is for this combination of reasons that ECV has long been seen as another option, and a way of potentially reducing the caesarean section rate and improving perinatal and maternal outcomes.
As the abstract below shows, the authors found eight relevant studies, which included the outcomes of 1308 women. The results show that ECV is effective, in that it does reduce the number of babies who are still in a breech position at term, and that it reduces the number of caesarean sections. There was not enough good data to be able to draw conclusions about whether ECV reduces perinatal mortality and morbidity, but the authors note that the data that are available from other studies suggest that complications from ECV are rare.
This is good news, but all reviews of this nature need to be considered in the context of the wider picture and debates. The wider debates in this area include the fact that much of the research on breech delivery has focused on interventive and medically-managed delivery (often including drugs, restricted maternal position, episiotomy and routine manipulation of the baby as it is born) rather than a more supportive approach which promotes physiological breech birth and where the practitioner intervenes only if there is a need to do so. Because of this, we need to be careful to recognise that the evidence in this area is almost all based on a medicalised approach, and that there may be more to learn from evaluating other methods of supporting women whose babies are in a breech position.
It is also worthy of note, however, that this is a really difficult area to research well. Among other issues, it is next to impossible to ‘blind’ participants or researchers to the method of delivery, and there may be differences in the way in which babies who are born head-first or bottom-first adapt to life outside the womb, which may affect their outcomes in the first few minutes of life. In another recent observational study (Beuckens et al 2015), the success rate of ECVs performed by trained midwives in primary health care or hospital settings in the Netherlands was found to be comparable with that of other providers, and the procedure was safe for low-risk women, but this kind of study is different from those that are included in the Cochrane review.
Background: Management of breech presentation is controversial, particularly in regard to manipulation of the position of the fetus by external cephalic version (ECV). ECV may reduce the number of breech presentations and caesarean sections, but there also have been reports of complications with the procedure.
Objectives: The objective of this review was to assess the effects of ECV at or near term on measures of pregnancy outcome. Methods of facilitating ECV, and ECV before term are reviewed separately.
Search methods: We searched the Cochrane Pregnancy and Childbirth Trials Register (28 February 2015) and reference lists of retrieved studies.
Selection criteria: Randomised trials of ECV at or near term (with or without tocolysis) compared with no attempt at ECV in women with breech presentation.
Data collection and analysis: Two review authors assessed eligibility and trial quality, and extracted the data.
Main results: We included eight studies, with a total of 1308 women randomised. The pooled data from these studies show a statistically significant and clinically meaningful reduction in non-cephalic presentation at birth (average risk ratio (RR) 0.42, 95% confidence interval (CI) 0.29 to 0.61, eight trials, 1305 women); vaginal cephalic birth not achieved (average RR 0.46, 95% CI 0.33 to 0.62, seven trials, 1253 women, evidence graded very low); and caesarean section (average RR 0.57, 95% CI 0.40 to 0.82, eight trials, 1305 women, evidence graded very low) when ECV was attempted in comparison to no ECV attempted. There were no significant differences in the incidence of Apgar score ratings below seven at one minute (average RR 0.67, 95% CI 0.32 to 1.37, three trials, 168 infants) or five minutes (RR 0.63, 95% CI 0.29 to 1.36, five trials, 428 infants, evidence graded very low), low umbilical vein pH levels (RR 0.65, 95% CI 0.17 to 2.44, one trial, 52 infants, evidence graded very low), neonatal admission (RR 0.80, 95% CI 0.48 to 1.34, four trials, 368 infants, evidence graded very low), perinatal death (RR 0.39, 95% CI 0.09 to 1.64, eight trials, 1305 infants, evidence graded low), nor time from enrolment to delivery (mean difference -0.25 days, 95% CI -2.81 to 2.31, two trials, 256 women). All of the trials included in this review had design limitations, and the level of evidence was graded low or very low. No studies attempted to blind the intervention, and the process of random allocation was suboptimal in several studies. Three of the eight trials had serious design limitations, however excluding these studies in a sensitivity analysis for outcomes with substantial heterogeneity did not alter the results.
Authors’ conclusions: Attempting cephalic version at term reduces the chance of non-cephalic presentation at birth, vaginal cephalic birth not achieved and caesarean section. There is not enough evidence from randomised trials to assess complications of ECV at term. Large observational studies suggest that complications are rare.
Hofmeyr GJ, Kulier R and West HM (2015). External cephalic version for breech presentation at term. Cochrane Database of Systematic Reviews, Issue 4. [DOI: 10.1002/14651858.CD000083.pub3]
Beuckens A, Rijnders M, Verburgt-Doeleman GHM (2015). An observational study of the success and complications of 2546 external cephalic versions in low-risk pregnant women performed by trained midwives. BJOG DOI: 10.1111/1471-0528.13234