The Early External Cephalic Version 2 Trial: An International Multicenter Randomized Controlled Trial of Timing of External Cephalic Version for Breech Pregnancies

ABSTRACT Intervention with an external cephalic version (ECV) procedure at term in a woman whose fetus presents in a breech position reduces the need for cesarean delivery and is considered safe for the fetus. Accordingly, the ECV procedure has been recommended for all eligible women with a breech fetus at term. Because of the risk of a failed procedure when ECV is not undertaken until term (≥37 weeks of gestation), it has been hypothesized that initiating ECV earlier than term may increase the likelihood of successful ECV and further reduce the need for cesarean delivery. The aim of this unblended, multicenter, randomized controlled trial was to determine whether initiation of ECV at 34 to 35 weeks of gestation in women presenting with a breech fetus would decrease the likelihood of cesarean delivery and reduce the risk of preterm birth (<37weeks of gestation). A total of 1543 women presenting with a singleton breech fetus were randomized by gestational age to receive the ECV procedure either between 33 0/7 weeks (231 days) to 35 6/7 weeks (251 days) of gestation (early ECV group, n = 765) or after 37 0/7 weeks (259 days) of gestation (delayed ECV group, n = 768). The primary outcome measure was the rate of cesarean delivery and the secondary outcome was the rate of preterm birth. There were fewer infants in a noncephalic presentation at birth in the early ECV group (41.1% [314/765]) than the delayed ECV group (49.1% [377/768]); the relative risk (RR) was 0.84, with a 95% confidence interval (CI) of 0.75 to 0.94; P = 0.002. No difference was found between groups in the rate of cesarean delivery (early ECV: 52.0% [398/765] vs. delayed ECV: 56.0% [430/768]; RR, 0.93; 95% CI, 0.85–1.02; P = 0.12). There was also no difference in the risk of preterm birth (early ECV: 6.5% [50/765] vs. delayed ECV: 4.4% [34/768]; the RR was 1.48, with a 95% CI of 0.97 to 2.26; P = 0.07). These findings show that initiation of early ECV at 34 to 35 weeks of gestation decreases the likelihood of a noncephalic presentation at birth, but does not necessarily reduce use of cesarean delivery and may increase the rate of preterm birth.