Predicting success of external cephalic version

Many authors have identified prognostic factors for external cephalic version success, but there has not been an attempt to integrate these factors into a simple, quantitative scoring system for predicting version success. Nor have any prognostic factors been prospectively tested.

We examined the clinical characteristics of 108 consecutive breech versions performed between 1984 and 1986. These characteristics were evaluated by stepwise linear regression and discriminate analysis to identify those factors associated with success. Five factors explained the majority of the variability in outcome (parity, placental location, dilation, station, and estimated fetal weight). A model was developed to incorporate the trends identified among these five variables to create a scoring system similar to that of Bishop. This scoring system was then applied to 286 women undergoing external cephalic version since October 1986.

There was a positive relationship between a rising version score and the likelihood of successful breech version. No versions were successful with a score < or = 2, and all breech versions were successful with a score of 9 or 10. The results of the version score may have significantly altered physician recommendations in more than one third of cases.

We believe that this simple, quantifiable scoring system is a refinement in our ability to predict the likelihood of external cephalic version success.