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

Abstract

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). 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 2x2 table were selected. 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. 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.