External cephalic version for breech presentation
Limited available data suggest that external cephalic version (ECV) before term reduces the risk of non-cephalic birth, and ECV at 34–35 weeks may reduce the risk of non-cephalic presentation and caesarean section. In practice, if appropriate precautions are taken, there are sound reason to use ECV at term if the benefits of avoiding a non-cephalic birth outweigh the risk of the procedure.
RHL Commentary by Lede R
Breech presentation at term occurs in around 3%–5% of pregnancies (1). Vaginal breech deliveries are associated with increased maternal and newborn morbidity and mortality. Hence, breech presentation is now recognized as an abnormality, even if conditions for labour are ideal and fetal diameters are compatible with maternal pelvic dimensions. During vaginal breech delivery, deflexion of the arms or head of the fetus can complicate childbirth, which can potentially harm the fetus. Currently, high-quality evidence shows that caesarean section is the method of choice to deliver a fetus in breech presentation (1). However, delivery by caesarean section does not completely eliminate the risk of a difficult delivery because removing the baby's head last through the incision in the uterus can pose problems.
External cephalic version (ECV) is proposed for the management of breech presentation. Although ECV is apparently safe and highly successful (in about 70% of cases) when it is attempted before term, it appears to be effective in reducing rates of vaginal breech delivery and caesarean section only when it is performed at term. This commentary is focused mainly on the Cochrane review on external cephalic version at term (2). In addition, in The Cochrane Library, there are three other Cochrane reviews on this topic: (i) External cephalic version for breech presentation before term (3); (ii) Cephalic version by postural management for breech presentation (4); and (iii) Interventions to help external cephalic version for breech presentation at term (5).
2. METHODS OF THE REVIEW
The reviewers searched the Cochrane Pregnancy and Childbirth Trials Register (September 2010), the Cochrane Central Register of Controlled Trials (2010, Issue 3) and PubMed (1966 to September 2010). They also performed hand-searches of 30 relevant journals and searched a further 44 journals plus monthly BioMed Central email alerts. No language restrictions were applied. Two reviewers assessed eligibility and trial quality and extracted the data. Trials were checked for quality of sequence generation, allocation concealment, blinding and other potential sources of bias. These procedures ensured that the search was comprehensive. Other methods used in the conduct of the review were adequate. Data presented in the text and tables of the review are clear and complete.
3. RESULTS OF THE REVIEW
Seven randomized controlled trials (with 1245 women) of ECV at or near term (with or without tocolysis) compared with no attempt at ECV in women with breech presentation were included. Pooled data revealed that ECV attempts resulted in a significant reduction in non-cephalic birth [risk ratio (RR) 0.46, 95% confidence interval (CI) 0.31–0.66] as well as in caesarean section (RR 0.63, 95% CI 0.44–0.90). There were no significant differences in the incidence of Apgar score rates less than seven at one minute or at five minutes, low umbilical artery pH levels, neonatal admission or perinatal death.
ECV before term yields high success rate, but it is followed by a high reversion rates too. One review (3) suggests that a policy of performing ECV before term (before 37 weeks' gestation) could be effective in reducing breech presentation at birth. A recently published trial (6), which is not included in this review, compared early (34–35 weeks) with late (after 37 weeks) ECV and found that while the early group had fewer non-cephalic presentations, there was no difference in the rates of caesarean sections between the two groups. On the other hand, when ECV was practiced at term, the non-cephalic presentation rate at delivery was lower than in the non-ECV group (32.6% vs. 78.3%). Caesarean section rate was not reduced when ECV was performed before term, but it was almost halved when it was performed at term (15.8% vs. 30.1%). To this end, caesarean section rates in individual studies varied between 8% and 28% in the ECV groups and 11% and 74% in the control groups. Undoubtedly, these figures reflect the different management policies for breech presentation at delivery. Also, limited data suggest that postural management regardless of ECV does not appear to contribute significantly to reduction in non-cephalic presentations.
4.1 Applicability of the results
Available data on EVC suggest that, compared with no ECV attempt, ECV before term reduces the risk of non-cephalic birth. Compared with ECV at term, attempting ECV at between 34 and 35 weeks may be associated with reduced risk of non-cephalic presentation and caesarean section. If proven useful in larger trials, ECV would be equally valuable in all settings, but especially in those where caesareans section may not be available and where caesareans sections rates are high.
Hence, if appropriate precautions are applied, there are sound reason for using ECV at term in any woman in whom the value of an improved chance of a cephalic birth outweighs the risk of the procedure. Post-hoc analyses suggested that ethnicity is not a factor in the success of ECV. Tocolysis during ECV has been proposed as a method to increase ECV success, but available data are limited.
4.2 Implementation of the intervention
Appropriate management of breech presentation requires timely antenatal diagnosis and appropriate attempts to avoid breech presentation at delivery. In under-resourced settings, when a persisting breech presentation is diagnosed or suspected, it is advisable to refer the patient to a hospital with operative facilities for ECV and eventual emergency caesarean section.
ECV is an inexpensive manoeuvre which can be performed in an outpatient clinic. It is done by applying gentle pressure over the maternal abdominal wall, directed first towards reducing fetal longitudinal axis and, then, to promote a forward somersault. Only one to three attempts are recommended. To repeat ECV attempts few days after failure is the usual practice, but it has not been specifically evaluated. ECV does not require a highly skilled practitioner, only a judicious one. Auscultation of the fetal heart rate during the procedure is recommended in order to detect fetal bradycardia, though this is not very common. Other complications such as vaginal bleeding, abruptio placentae and fetal death are rare.
ECV should be attempted for women at term with no contraindications. Prior to attempting ECV fetal presentation should be accurately determined. This can usually be accomplished by a careful clinical examination. It is also important to know the gestational age of the fetus and to get the parents' authorization. ECV does not require very special conditions for its successful implementation; an examination table and a fetal stethoscope are adequate. To confirm fetal presentation it is advisable to get a second opinion from a senior obstetrician/midwife. If available, an ultrasonograph exam should also be used. Immediate availability of operative facilities is recommended before attempting ECV.
4.3 Implications for research
Further research is needed on: the role of ECV in the management of breech presentation during labour; the value of interventions (such as tocolytics agents, fetal acoustic stimulation, maternal regional analgesia) in conjunction with ECV; the role of ECV in the second twin in breech presentation and after the rupture of amniotic membranes. Given that available trials do not give information on women's views on this potentially important procedure, research into this area will also be helpful.
Source of support: Argentine Institute for Evidence Based Medicine (IAMBE).
- Hofmeyr G Justus, Hannah Mary. Planned caesarean section for term breech delivery. Cochrane Database of Systematic Reviews. In: The Cochrane Library, Issue 06, Art. No. CD000166. DOI: 10.1002/14651858.CD000166.pub2
- Hofmeyr GJ, Kulier R. External cephalic version for breech presentation at term. Cochrane Database of Systematic Reviews 1996, Issue 1. Art. No.: CD000083. DOI: 10.1002/14651858.CD000083.
- Hutton EK, Hofmeyr GJ. External cephalic version for breech presentation before term. Cochrane Database of Systematic Reviews 2006, Issue 1. Art. No.: CD000084. DOI: 10.1002/14651858.CD000084.pub2.
- Hofmeyr GJ, Kulier R. Cephalic version by postural management for breech presentation. Cochrane Database of Systematic Reviews 2000, Issue 3. Art. No.: CD000051. DOI: 10.1002/14651858.CD000051.
- Hofmeyr GJ, Gyte GML. Interventions to help external cephalic version for breech presentation at term. Cochrane Database of Systematic Reviews 2004, Issue 1. Art. No.: CD000184. DOI: 10.1002/14651858.CD000184.pub2).
- Hutton EK, Hannah ME, Ross SJ, et al.; Early ECV2 Trial Collaborative Group. The Early External Cephalic Version (ECV) 2 Trial: an international multicentre randomised controlled trial of timing of ECV for breech pregnancies. BJOG 2011;118:564-77; doi: 10.1111/j.1471-0528.2010.02837.x. Epub 2011 Feb 4.
This document should be cited as: Lede R. External cephalic version for breech presentation at term: RHL commentary: (last revised: 1 December 2011). The WHO Reproductive Health Library; Geneva: World Health Organization.