So your baby is breech!?
About 25% of babies will be breech at 28 weeks, but by term (37 weeks plus) only 3-4% of babies are. Your provider will assess fetal position throughout the third trimester with Leopold Maneuvers (gently feeling head, back and extremities with our hands on your belly). Generally by 34 weeks or so it is easy to tell if baby is head down or not, and if we can’t easily feel, we will perform an ultrasound in the 36th week. If breech presentation is confirmed at 36 weeks, we will discuss whether or not you want us to try to rotate your baby to a head down position. That is, if you want an external cephalic version!
What is an External Cephalic Version?
External cephalic version is a procedure done in the hospital by your OB doctor. Manual pressure is applied to your belly in order to roll baby from breech to a head down position. External cephalic version is successful 58% of the time (that is what the literature suggests but anecdotally success is lower than this). A variety of factors can impact that success rate up or down. For instance, having had a baby before, normal to high amniotic fluid level, normal maternal body weight and posterior location of the placenta can all improve the chances of successfully turning baby to head down. When considering if external cephalic version is right for you, talk with your doctors about the particular features of your pregnancy that could impact your success. External cephalic version is done in a hospital setting because about 5% of the time, the procedure is complicated by an abnormal fetal heart rate tracing. Typically when this occurs it is a transient response to the procedure, but 1% of the time more serious complications can occur and we want to be in the position to perform a cesarean delivery if needed.
To turn or not to turn
So why would you choose to have an external cephalic version? Because the risks for baby associated with breech vaginal birth are higher than head down vaginal birth, and higher than planned cesarean delivery. The superiority of planned cesarean birth for breech fetal presentation was established in a large study published in 2000, the Term Breech Trial. Researchers randomly assigned 2088 women with breech fetuses to either planned cesarean or vaginal birth and followed them and their babies out to 6 weeks postpartum. They found that babies born by planned cesarean did better, with significantly fewer injuries and deaths in that group. Given the results of this high quality study, breech vaginal birth is generally not recommended.
Why try to turn baby instead of just going for a planned C-section? Because vaginal birth carries fewer risks than a cesarean birth (cesarean delivery, of course, carries surgical risks in addition to the risks of childbirth). External cephalic version, when successful, can allow patients with a breech baby the opportunity to try for a vaginal birth.
Hannah ME, Hannah WJ, Hewson SA, Hodnett ED, Saigal S, Willan AR. Planned caesarean section versus planned vaginal birth for breech presentation at term: a randomised multicentre trial. Term Breech Trial Collaborative Group. Lancet. 2000 Oct 21;356(9239):1375-83. doi: 10.1016/s0140-6736(00)02840-3. PMID: 11052579.
Shanahan MM, Gray CJ. External Cephalic Version. [Updated 2022 Jul 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482475/
