External cephalic version: predictors of success

Objective: To evaluate predictive variables for successful external cephalic version. Methods: During 1987–1996, 128 women had external cephalic version attempts. Uterine tone, fetal spine position, breech location, breech type, gestational age, placental location, parity, maternal weight, amniotic fluid index, and estimated fetal weight were evaluated as predictors of success. Results: Seventy-eight (64%) women were successfully converted from breech to vertex presentation. All subjects with low uterine tone had successful version. In women with high uterine tone, the combination of anterior or lateral fetal spine, noncornual placental location, and breech location out of the pelvis predicted success. Other independent variables associated with successful version included nonfrank breech presentation, gestational age under 38 weeks, and parity of at least 1. Conclusion: Uterine tone may be the most important predictor of success when selecting candidates for external cephalic version.