How common is the breech position?
Breech position (bottom first) is present in 3 to 4% of term pregnancies. Breech positioning is more common prior to term—25% are breech before 28 weeks, but by 32 weeks only 7% of babies are breech. The vast majority of breech babies in the U.S. are now born by planned C-section. The use of a safe procedure to help turn babies into a head-down position (aka cephalic position), may help reduce the C-section rate (Lannie and Seeds 2012).
Here are some statistics that I compiled from the Centers for Disease Control. As you can see, there were 43,137 breech babies in the U.S. during the year 2010. Of these babies, 90% were born by C-section. The number of known breech births made up 4% of all C-sections in 2010.
Note: These statistics do not tell us how many of these were pre-term births or twin births. Also, the delivery method and positioning were not always listed on the birth certificate. The inaccuracy of birth certificate data is well known. For example, the data show that 187 breech babies were born with vacuum assistance, which is not possible at a breech birth. So this table does not give us a perfect picture of how many singleton babies are in the breech position at birth—but rather it gives us an approximate idea.
What is an external cephalic version?
External = from the outside, cephalic = head first, version = turning
An external cephalic version is when a care provider puts his or her hands on the outside of the mother’s belly and turns the baby into a head-down position. This is also called an ECV, version, or “hands to belly” procedure (Lannie and Seeds 2012).
How many women with breech babies have a version?
The exact percentage of women who undergo a version for breech positioning is unknown. Using the CDC’s Vital Statistics program, I was able to make some calculations. Note– I was not able to find this information anywhere else on the internet. As far as I can tell, I am the first person to publish an article using these statistics. As you can see in the table below, there were approximately 3,942 successful external cephalic versions in the U.S. Of these successful versions, 2,858 (73%) of women went on to have vaginal births. On the other hand, there were 2,622 failed version procedures in 2010, and the majority of those women went on to have surgical births (2,238 or 85%).
It is possible that the version is an underused procedure. In an Australian study, only 66% of pregnant women had ever heard of a version, and most of these women (87%) learned about version from books or family/friends—not from care providers. Only 39% of women in the study said they would choose a version if they had a breech baby, and 22% were undecided. Women who did not want a version said that they had concerns about effectiveness and safety for the baby (Raynes-Greenow, Roberts et al. 2004).
In a Dutch study, investigators estimated that less than half of women in the Netherlands with a breech baby at term had a version. Approximately 20-30% of women refused a version and decided to have a planned C-section instead. It was estimated that anywhere from 4 to 33% of women are not given the option of a having a version by their care providers (Vlemmix, Rosman et al. 2010).
Are external cephalic versions effective for reducing the risk of C-section?
In a Cochrane review, Hofmeyr and Kulier combined the results from 7 randomized, controlled trials with 1,245 women who were randomly assigned to either external cephalic version or no treatment. The quality of the studies was mixed. In order to control for quality of the studies, the researchers looked at the results both with and without the poorer quality studies. When they did so, the results stayed the same.
Overall, the researchers found that having an external cephalic version decreased the risk of breech birth by 54% and decreased the risk of C-section by 33%. There were no differences in any other outcomes, including Apgar scores, neonatal admission, or infant deaths. The studies did not look at maternal satisfaction (Hofmeyr and Kulier 2000).
It is important to note that 5 of the 7 studies in this review took place between 1981 and 1991, a time when breech vaginal deliveries were more common. Since the publication of the “Term Breech Trial” in 2000, breech vaginal deliveries have become extremely rare, and most breech babies are born by planned C-section. Therefore, it is possible that if these studies were replicated today, having an external cephalic version might result in an even larger reduction in the risk of C-section.
What are the risks of an external cephalic version?
The sample sizes from the previously mentioned Cochrane were too small to give an accurate picture of rare risks of an external cephalic version. In order to look at risks, we need to look at systematic reviews of observational studies. There have been three systematic reviews in which authors compiled all the evidence about risks of external cephalic version. All three studies found that serious complications are rare. In this article, I will only talk about the most up to date systematic review.
In 2008, Grootscholten et al. pooled the results of 84 studies that included 12,955 women. 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 were 12 stillbirths out of the 12,955 cases, and only 2 of these deaths were related to the version. The other deaths were un-related to the external version or unexplained. The unexplained stillbirths were diagnosed 10 to 31 days after the version. Placenta abruption occurred in 0.18% of women (11 abruptions out of 12,955 versions), and 10 of these abruptions resulted in an emergency C-section (Grootscholten, Kok et al. 2008).
Other complications included cord prolapse (0.18%), temporary abnormal fetal heart rate patterns (4.7%), vaginal bleeding (0.34%), and water breaking (0.22%). There was 1 urgent C-section for every 286 versions. In summary, researchers found that external cephalic version is safe, but they recommended that a version should take place in a setting where an urgent C-section could be performed if necessary.
Are there any techniques that increase the likelihood of a successful version?
Researchers have studied several techniques that could increase the chance of a success with a version. So far, the most helpful technique seems to be using drugs to prevent labor contractions (aka tocolysis). In a Cochrane review, researchers combined the results of 25 studies with more than 2,500 women who were randomly assigned to receive version alone or version with an additional technique, such as tocolysis or having an epidural.
Women who were randomly assigned to receive tocolytic drugs during the version were 18% less likely to end up with an eventual C-section for breech positioning compared to women who did not receive tocolysis. Women who received tocolysis were also 38% more likely to have babies with head-first positioning at birth (Cluver, Hofmeyr et al. 2012).
Women who were randomly assigned to have an epidural or spinal (in combination with tocolysis) during the version were 33% more likely to have a successful version. There were no differences in any of the other outcomes between women with and without epidurals. However, the numbers of women in the epidural studies are probably too small to give us a clear picture of the effects of epidurals on versions (Cluver, Hofmeyr et al. 2012).
Are there any other factors that may influence the success rate of versions?
Women are more likely to have a successful version if they have had previous children, if the baby is not engaged in the pelvis, if the uterus is relaxed during the procedure, if the mother is not overweight, and if the care provider can feel the baby’s head on palpation. Gestational age (whether the mother is <37 weeks, 37, 38, 39, or >39 weeks) has no effect on success rates. (Kok, Cnossen et al. 2008)
There are also some things that can be seen on an ultrasound that may influence the success rate of a version. If a baby is in the “complete breech” position (buttocks down, with the legs folded at the knees and the feet near the buttocks) this increases the chance that the version will be successful. Version is also more likely to be successful if the placenta is posterior (on the back side of the uterus) and if there are normal levels of amniotic fluid (an Amniotic Fluid Index >10) (Kok, Cnossen et al. 2009).
Are there any reasons why someone cannot have a version?
Different guidelines list different reasons why certain women should not have a version. Whenever there is a reason not to do something, that reason is called a “contraindication.” In 2012, researchers did a systematic review to determine which contraindications are based on research evidence (Rosman, Guijt et al. 2012).
For the 39 different contraindications listed in international guidelines, the researchers could only find evidence for 6 of these. In other words, 33 of the 39 contraindications were based on clinical opinion alone. Of the six contraindications that had research evidence, five of these could probably be rejected because of the evidence. The research evidence does NOT support these contraindications for a version: having had a previous C-section, fetal growth restriction, suspected big baby, low amniotic fluid, and high amniotic fluid. (I plan to write a separate article about versions for women with a previous C-section, so stay tuned for the evidence on that topic!)
The authors concluded that there is good evidence—based on both research and physiology— that women should NOT have a version if they have a history of placenta abruption or if placenta abruption is suspected, if there is a diagnosis of severe pre-ecclampsia, or if there are signs of fetal distress.
It is important to note that although there may be little research evidence to back up some contraindications, some care providers may use their expert opinion to recommend against a version in certain circumstances. A care provider may anticipate a difficult version, a low likelihood of success, or perhaps that the benefits do not outweigh the risks. For example, a care provider may not want to perform a version on someone with very low amniotic fluid because that increases the difficulty of the procedure. Other care providers might not want to perform a version if the baby has the umbilical cord wrapped around the neck. Although there is no solid research on these topics, the care provider’s clinical opinion may be that the procedure may be too difficult, or that the risks of the procedure outweigh the benefits.
When is the best time to have a version?
There are two basic times when you can choose to have a version: before term (34 to 37 weeks) or at term (>37 weeks). In a large, randomized controlled trial that compared before term and at term versions, researchers found that doing a version before term increases the chance that the baby will be head down at birth. However, they also found that having an early version does not reduce the risk of having a C-section. There was also evidence that doing a version before term may increase the risk of premature birth (Hutton, Hannah et al. 2011).
In another systematic review, researchers found that gestational age was NOT a predictor of success during a version (Kok, Cnossen et al. 2008). Based on these findings, it seems that there is no single best time to attempt a version—instead, women and care providers should discuss the risks and benefits of early versus later versions.
In summary, the evidence shows that:
- More than half of external cephalic versions (58%) will turn a baby to a head-down position
- Benefits include a significant decrease in the risk of C-section and a decrease in breech positioning at birth
- The most common risk is a temporary change in the infant’s heart rate (4.7%); serious complications are rare (0.24%)
- Guidelines on version from the Royal College of Obstetricians and Gynecologists (United Kingdom)
- Guidelines on version from the American Academy of Family Physicians
Dr. Danny Tucker turns a breech baby with an external cephalic version
- Cluver, C., G. J. Hofmeyr, et al. (2012). “Interventions for helping to turn term breech babies to head first presentation when using external cephalic version.” Cochrane Database Syst Rev 1: CD000184.
- Grootscholten, K., M. Kok, et al. (2008). “External cephalic version-related risks: a meta-analysis.” Obstetrics and gynecology 112(5): 1143-1151.
- Hofmeyr, G. J. and R. Kulier (2000). “External cephalic version for breech presentation at term.” Cochrane Database Syst Rev(2): CD000083.
- Hutton, E. K., M. E. Hannah, et al. (2011). “The Early External Cephalic Version (ECV) 2 Trial: an international multicentre randomised controlled trial of timing of ECV for breech pregnancies.” BJOG : an international journal of obstetrics and gynaecology 118(5): 564-577.
- Kok, M., J. Cnossen, et al. (2008). “Clinical factors to predict the outcome of external cephalic version: a metaanalysis.” Am J Obstet Gynecol 199(6): 630 e631-637; discussion e631-635.
- Kok, M., J. Cnossen, et al. (2009). “Ultrasound factors to predict the outcome of external cephalic version: a meta-analysis.” Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology 33(1): 76-84.
- Lannie, S. M. and J. W. Seeds (2012). Malpresentations and shoulder dystocia. Obstetrics: Normal and Problem Pregnancies. S. G. Gabbe. Philadelphia, PA, Saunders.
- Raynes-Greenow, C. H., C. L. Roberts, et al. (2004). “Pregnant women’s preferences and knowledge of term breech management, in an Australian setting.” Midwifery 20(2): 181-187.
- Rosman, A. N., A. Guijt, et al. (2012). “Contraindications for external cephalic version in breech position at term: a systematic review.” Acta obstetricia et gynecologica Scandinavica.
- Vlemmix, F., A. N. Rosman, et al. (2010). “Implementation of the external cephalic version in breech delivery. Dutch national implementation study of external cephalic version.” BMC Pregnancy Childbirth 10: 20.