External Cephalic Version: A Review of the Evidence

External cephalic version (ECV) is an obstetric maneuver that rotates the fetus to a cephalic presentation in case of breech, oblique or transverse lie presentations. During the past 14 years, the most relevant studies (n >200 patients) reveal success rates ranging from 37% to 78.7%. The contraindications of ECV are: when a clear indication for a cesarean delivery exists, fetal compromise, placenta praevia, placenta abruption, intrauterine fetal death, rupture of membranes, multiple gestation, Rh sensitivization, uterine abnormalities and coagulation disorders. ECV was only contraindicated in 4% of breech presentations. Many authors have examined the factors associated with ECV success rate. We did not identify any factor that showed a constant association across all studies. The goal of describing factors associated with ECV success rate is to determine whether they can be enhanced, thus contributing to improve ECV success rate. Studies have focused on three different actuations: tocolysis, regional analgesia and amnioinfusion. ECV is not alien to complications, although the risk of complications remains low when performed correctly. The reported complications are transitory alteration of cardiotocography, feto-maternal transfusion, urgent cesarean delivery, perinatal mortality, vaginal hemorrhage, premature detachment of the placenta. The final goal of ECV is to decrease the presence of breech presentations at the time of labor and thus reduce the rate of cesarean sections. A meta-analysis of the Cochrane review observed a significant decrease in the rate of cesarean sections (RR=0.52; CI95%=0.39-0.71) in patients subject to ECV at term without worse perinatal outcomes.