Ultrasound factors to predict the outcome of external cephalic version: A meta-analysis

Objective: To systematically review the medical literature reporting on ultrasound factors that can be predictive for the outcome of an attempt at external cephalic version (ECV). Methods: MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials were searched. Studies reporting on potential ultrasound prognosticators and ECV success rates that allowed construction of a 2 x 2 table were selected. Results: We selected 37 primary articles reporting on 7709 women. Posterior placental location (odds ratio (OR), 1.9; 95% CI, 1.5-2.4), complete breech position (OR, 2.3; 95% CI, 1.9-2.8) and an amniotic fluid index > 10 (OR, 1.8; 95% CI, 1.5-2.1) were predictors of successful ECV. Conclusion: Success of an ECV attempt is associated with ultrasound parameters such as fetal position, amniotic fluid and placental location. This knowledge can be used to develop a prognostic model to predict successful ECV.