Abbie Tomson
Midwife, Project Lead for All4Birth
@All4Birth
Summary
ECV, or External Cephalic Version, aims to turn a breech baby in the womb to a head-down position. This non-invasive technique involves applying pressure on the mother’s abdomen to coax the baby into the optimal position. This factsheet will explore what ECV is, how it’s performed, and its potential benefits and risks. We will also discuss the factors that may increase or decrease the success rate of ECV.
What is an External Cephalic Version (ECV)?
External cephalic version (or ECV) is where an obstetrician uses their hands on your abdomen to turn your baby, using a forward or backward roll into a head-down (or cephalic) position. The success rate of ECVs is approximately 50%, and if unsuccessful at 36 weeks gestation or later 1, statistics suggest that only a few babies with breech presentation will spontaneously turn to cephalic presentation. However, if successful, few babies revert to breech presentation.
What is the evidence?
A Cochrane Review 2 combined the results from eight randomised controlled trials (RCT) with 1308 participants who were randomly assigned to either an ECV or no treatment. Overall, the researchers found that attempting an ECV at term (after 37 weeks gestation) decreased the relative risk (decreasing the relative risk indicates a lower probability of a negative outcome in a particular group compared to another group) of breech birth by 58% and decreased the relative risk of caesarean birth by 43%. However, there were no differences in other outcomes, including neonatal admission or infant deaths. It is important to note that the quality of the studies was mixed, but the researchers in this case looked at the results both with and without the poorer quality studies and found the same results.
A much larger review 3 included two randomised controlled trials (conducted in 1981 and 1984) with seven observational studies comparing the effects of ECV or no ECV but included 184,000 pregnant women and people eligible for an ECV at and including 36 weeks gestation. A total of 7000 (check) ECVs were attempted within this. It was found that attempted ECV was linked to a significant reduction in caesarean and non-head down position at birth. However, they also found that ECV attempts were linked to a slightly increased rate of Apgar score being low at 5 minutes compared to a no ECV attempt. But overall. Attempted ECV had no effect on low Apgar scores at 1 minute, infant death or neonatal admission. It is important to note that an unclear risk of bias limited this review but provided us with interesting evidence, given the large number of participants included.
A study with more participants attempting an ECV was conducted in 2008 4 , where the researchers combined the results of 84 studies that included 12,955 participants who experienced an attempted ECV. They only included studies that reported on complications from attempted versions on single babies done after 36 weeks of pregnancy. The average success rate for turning a baby out of the breech position was 58%. The overall complication rate was 6%, and the rate of serious complications (placenta abruption or stillbirth) was 0.24%. There was one urgent Cesarean for every 286 ECVs. In summary, researchers found that ECV is safe, but they recommended that a version occur where an emergency caesarean birth could be performed if necessary.
What does the evidence say about factors associated with success?
- Hutton et al. (2017) 5 found that the following factors are strongly linked to higher ECV success rates:
- Having given birth to previous children
- If the baby is not engaged in the pelvis,
- If the care provider can easily feel the baby’s head on palpation
Other factors that increase the likelihood of an ECV’s success (although not as statistically related as the above) 5, 6
- Posterior placenta
- A BMI of less than 32.7
- Normal levels of amniotic fluid
- Intact waters
- Normally shaped uterus
- Relaxed abdominal muscles
- Non-frank breech presentation
What can increase the rate of success?
In a Cochrane Review 7, researchers combined the results of 28 studies with more than 2,700 participants randomly assigned to receive an ECV alone or ECV with an additional technique, such as tocolytic (drugs to prevent contractions) or having an epidural. The participants who were randomly assigned to receive tocolytic drugs during the ECV were 23% less likely to have an eventual caesarean birth for breech positioning compared to those who did not receive tocolysis. Participants who received tocolysis were also 68% more likely to have babies with head-first positioning at the start of labour.
However, those who were randomly assigned to have an epidural or spinal (as well as tocolysis) during the ECV were 39% more likely to have a successful ECV. There were no differences in any of the other outcomes between participants with and without epidurals, such as a head-down presentation at the start of labour or rate of caesarean births, but the number of participants in the study (279 people) may not have been large enough to find an effect. Of note, epidurals or spinal are seldom offered for ECVs in the UK because they make for a much longer and more complicated procedure.
What don’t we know?
There is a low uptake of ECVs, with future research needing to investigate why. In 2017, an Australian study 8 looked at over 32,000 people who had singleton breech pregnancies after 36 weeks gestation and found that only 10.5% of the group attempted an ECV. As many as 67.2% did not attempt an ECV even though they were good candidates for the procedure (in line with Australian practice guidelines). The researchers noted that it was unclear whether the low rate of ECV attempts was related to failure to offer from health professionals or pregnant women and people declining the procedure.
OptiBreech has proposed research to look at this. The aim of this research is to determine if attempting an ECV offers additional benefits compared to OptiBreech care with no ECV. The design is a randomised controlled trial, with women over 36 weeks of pregnancy who wish to plan a vaginal birth regardless of whether their baby remains in a breech position. Those who participate will be randomly allocated to one of two options. The ‘standard care’ group (the control) will have an ECV attempt. If unsuccessful, the person will plan a vaginal breech birth with OptiBreech care. The experimental group will be no-ECV; these will plan a vaginal breech birth with OptiBreech care. They will compare these two groups to determine whether the vaginal birth rate differs between them and whether caring for one group costs more than caring for the other 9.
Links to other resources
Books
BooksAIMS: Breech birth: What are my options?
Guidelines
GuidelinesPrint Media
Print Media
Podcast
WebsitesReferences
Please use the latest/most notable references for this topic. Use AMA numerical referencing. Guide at end.
- Grootscholten, K., Kok, M., Oei, S. G., Mol, B. W., & van der Post, J. A. (2008). External cephalic version-related risks: a meta-analysis. Obstetrics and gynaecology, 112(5), 1143–1151. https://doi.org/10.1097/AOG.0b013e31818b4ade
- Hutton, E. K., Hofmeyr, G. J., & Dowswell, T. (2015). External cephalic version for breech presentation before term. The Cochrane database of systematic reviews, 2015(7), CD000084. https://doi.org/10.1002/14651858.CD000084.pub3
- much larger review 7000 odd people need to update participants in
- Grootscholten, K., Kok, M., Oei, S. G., Mol, B. W., & van der Post, J. A. (2008). External cephalic version-related risks: a meta-analysis. Obstetrics and gynaecology, 112(5), 1143–1151. https://doi.org/10.1097/AOG.0b013e31818b4ade
- Hutton, E. K., Simioni, J. C., & Thabane, L. (2017). Predictors of success of external cephalic version and cephalic presentation at birth among 1253 women with a non-cephalic presentation using logistic regression and classification tree analyses. Acta obstetricia et gynecologica Scandinavica, 96(8), 1012–1020. https://doi.org/10.1111/aogs.13161
- Lim, S., & Lucero, J. (2017). Obstetric and Anesthetic Approaches to External Cephalic Version. Anesthesiology clinics, 35(1), 81–94. https://doi.org/10.1016/j.anclin.2016.09.008
- Cluver, C., Gyte, G. M., Sinclair, M., Dowswell, T., & Hofmeyr, G. J. (2015). Interventions for helping to turn term breech babies to head first presentation when using external cephalic version. The Cochrane database of systematic reviews, 2015(2), CD000184. https://doi.org/10.1002/14651858.CD000184.pub4
- Bin, Y. S., Roberts, C. L., Nicholl, M. C., & Ford, J. B. (2017). Uptake of external cephalic version for term breech presentation: an Australian population study, 2002-2012. BMC pregnancy and childbirth, 17(1), 244. https://doi.org/10.1186/s12884-017-1430-5
- Inviting your views: OptiBreech ECV or no-ECV trial
