Predictors of failed operative vaginal delivery: a single-center experience

Objective: The purpose of this study was to identify factors that predict operative vaginal delivery. Study Design: A retrospective cohort study was conducted that included all women who underwent a trial of operative vaginal delivery between 1993 and 2006 at a major tertiary center. Results: Operative vaginal delivery was attempted in 5120 of 83,351 deliveries (6.1%): 4299 vacuum extractions (84.0%) and 821 forceps deliveries (16.0%). Failures occurred in 8.6% of trials, more often with vacuum extraction (10.0% vs 1.3%; P < .001). Most vacuum extraction failures (72.6%) were followed by a trial of forceps delivery, which failed in 3.5% of cases. On multivariate logistic regression analysis, the use of forceps (vs vacuum; odds ratio [OR], 0.4; 95%CI, 0.2-0.7) and administration of analgesia (epidural: OR, 0.4 [95% CI, 0.2-0.7]; intravenous opiates: OR, 0.2 [95%CI, 0.1-0.6]) were associated with a lower risk of failure, persistent occiput posterior position (OR, 2.2; 95% CI, 1.4-3.5) and birthweight >4000 g (OR, 2.8; 95% CI, 1.6-4.9), with a higher risk. Conclusion: Fetal weight and head position should be evaluated carefully before operative vaginal delivery, and the use of analgesia should be encouraged.