A prospective study of the factors associated with the success rate of external cephalic version for breech presentation at term

OBJECTIVE: To determine the factors associated with the success rate of external cephalic version (ECV) for breech presentation at term. METHODS: A prospective analysis of 500 ECV maneuvers. The variables maternal age, maternal weight, body mass index, previous cesarean delivery, gestational age, parity, amount of amniotic fluid, placental location, and type of breech were studied using logistic regression analysis. RESULTS: The success rate of ECV was 52.2% (n=261). The variables significantly associated with success were parity, placental location, amount of amniotic fluid, and type of breech (P<0.05). A parity of 2 had a 3.74-times higher probability of success than nulliparity (95% CI, 2.37-5.90); a posterior placenta increased the success rate by 2.85 times compared with an anterior placenta (95% CI, 1.87-4.36); and double footling breech presentation had a 2.77-times higher success rate compared with a frank breech presentation (95% CI, 1.16-6.62). The area under the ROC curve showed a predictive ability of 73.6% (95% CI, 69.2%-77.9%) for these 3 variables. CONCLUSION: Parity, placental location, amount of amniotic fluid, and type of breech presentation were associated with the success rate of ECV.