The best timing of ECV is controversial. It has been modified from later than 36 weeks’ gestation to early term—37 weeks or greater. When compared with term ECV (37+ weeks), preterm ECV (34–35 weeks) has been associated with increased short-term success with cephalic presentation, higher rates of reversion to breech in the ensuing weeks, and cesarean delivery risk reduction [RR 0.90; 95% CI 0.83–0.97]. However, preterm ECV is also associated with an increased risk of premature birth [RR 1.51; 95% CI 1.03–2.21].3
The current recommendation for ECVs at term could reduce their frequency and prevent unnecessary prematurity at the expense of a potentially small increase in cesarean delivery risk.
Parenteral tocolysis (beta agonist) should be used if there are no contraindications. Many of us already use some form of tocolysis to reduce uterine tone. Recent data support what many of us have suspected—that a tocolytic improves ECV success [RR 1.68; 95% CI, 1.14–2.48] and reduces cesarean delivery risk [RR 0.77; 95% CI, 0.67–0.88]. Although my experience has been with either magnesium or terbutaline, ACOG recommends the latter, citing insufficient evidence to support the use of alternative tocolytics.4
Is early labor or prior uterine scar a contraindication to ECV? Information is insufficient to make clear recommendations on this practice. The likelihood of success is not likely to significantly differ from that in women without these conditions, however, the magnitude of pregnancy risk has not been quantified due to insufficient study. ACOG does not consider these conditions to be contraindications to ECV and care of women in these situations should be individualized.
Whether to offer regional anesthesia at the time of ECV remains unclear, with discordant results in randomized trials exploring this question. Although there are some advantages, such as being able to offer cesarean delivery immediately if complications arise, the data do not currently support routine use. A recent meta-analysis demonstrated greater immediate ECV success, but did not show a significant reduction in cesarean delivery risk with regional anesthesia [RR 0.80; 95% CI, 0.55–1.17]. These findings did not differ for spinal or epidural.5
Although many factors have been associated with success and failure, unlike predicting successful trial of labor after cesarean section, no reliable or validated scoring system exists to counsel patients regarding their likelihood of avoiding a cesarean delivery.
Non-stress test monitoring should occur before and after ECV. Testing should continue for at least 30 minutes after the procedure. Anti-D immune globulin should be given to Rh-negative mothers who have no plans for delivery within 72 hours after ECV.
This new ACOG guidance is a reminder of the importance of routine screening for malpresentation in the third trimester. The evidence justifies ECV as a critical tool for providers to prevent cesarean delivery. Moreover, available evidence continues to be a useful guide for accomplishing a safe and effective ECV.
1. External cephalic version. Practice Bulletin No. 161. American College of Obstetricians and Gynecologists. Obstet Gynecol. 2016;127:e54-61.
2. Hofmeyr GJ, Kulier R, West HM. External cephalic version for breech presentation at term. Cochrane Database Syst Rev. 2015:4.
3. Hutton EK, Hofmeyr GJ, Dowswell T. External cephalic version for breech presentation before term. Cochrane Database Syst Rev. 2015:7.
4. Cluver C, Gyte GM, Sinclair M, Dowswell T, Hofmeyr GJ. Interventions for helping to turn term breech babies to head first presentation when using external cephalic version. Cochrane Database Syst Rev. 2015:2.
5. Goetzinger KR, Harper LM, Tuuli MG, Macones GA, Colditz GA. Effect of regional anesthesia on the success rate of external cephalic version: a systematic review and meta-analysis. Obstet Gynecol. 2011:118(5):1137-44.