Predictive score for vaginal birth after cesarean section.

OBJECTIVE

Our purpose was to evaluate the relative weight of the different variables that may influence the chances of vaginal birth after one cesarean delivery, with the aim of developing a predictive score for success of such a trial.

STUDY DESIGN

In this retrospective study, which covered a 10-year period (1981 to 1990), 471 women who attempted vaginal birth at a level III university hospital after one abdominal delivery were studied as to the subsequent delivery outcome. An attempt to identify possible prognostic factors for success of such a trial was made.

RESULTS

A trial of labor was successful in 368 (78.1%) of women and 103 (21.9%) had a repeat cesarean section. Variables of significant predictive value were vaginal birth before cesarean section (odds ratio 1.8), malpresentation (odds ratio 1.9), pregnancy-induced hypertension (odds ratio 2.3), and Bishop score > or = 4 (odds ratio 6.0). Cephalopelvic disproportion and failure to progress did not demonstrate a significant predictive value (odds ratio 0.81) for success or failure in subsequent delivery. In fact, 63.8% of women with this indication have successfully undergone vaginal delivery. Maternal age (odds ratio 0.9) had no bearing on vaginal delivery success rates, whereas both macrosomia (odds ratio 0.2) and intrauterine growth retardation tended to decrease the chances for vaginal birth after cesarean section.

CONCLUSIONS

A trial of labor after one cesarean section should be encouraged in most women who are willing to attempt it, provided no obstetric contraindication exists. A scoring system that may help to identify women with a greater chance for vaginal delivery is proposed.