Factors predictive of failed operative vaginal delivery.

OBJECTIVE: The purpose of this study was to determine what factors are independently associated with an increased likelihood of failed operative vaginal delivery.

STUDY DESIGN: We conducted a population-based case-control study evaluating maternal, pregnancy, provider, care setting, and fetal factors associated with failed operative vaginal delivery. Subjects were identified using Washington state birth certificates for infants born between 1992 and 2001. Cases (n = 1750) were live-born singletons with both labored cesarean delivery and an operative vaginal delivery ("failure") coded on the birth certificate. Controls (n = 3500), frequency matched by delivery year to the cases, were randomly selected from among singletons undergoing a successful operative vaginal delivery. Odds ratios (OR) and associated 95% CI, estimated with Mantel-Haenszel methods, measured the association between case status and potential risk factors.

RESULTS: Failed operative vaginal delivery was associated with increased maternal age, African American race, higher body mass index (BMI), diabetes, polyhydramnios, induction of labor, dysfunctional labor, and prolonged labor. Case compared with control mothers were more likely to deliver a low-birth weight or macrosomic infant.

CONCLUSION: Identification of maternal and fetal factors associated with failed operative vaginal delivery may enable providers to better counsel patients, and allow improved planning and allocation of surgical resources.