Timing of operative vaginal delivery and associated perinatal outcomes in nulliparous women.

OBJECTIVE: To compare perinatal outcomes in nulliparous women who had operative vaginal delivery early during second stage (1-3 h) to those who delivered vaginally with a prolonged second stage (>3 h).
METHODS: This is a retrospective cohort study of nulliparas with term, singleton, vaginal deliveries beyond the first hour of second stage. Women who underwent operative vaginal deliveries (OVD) during 1-3 h of the second stage were compared to women who delivered vaginally but with a second stage duration of >3 h. Perinatal outcomes were examined using chi-square test, and potential confounders were controlled for using multivariable logistic regression analysis.
RESULTS: Nulliparas delivered vaginally beyond 3 h of second stage had lower odds of third or fourth degree perineal lacerations (aOR = 0.63, 95% CI 0.51-0.77), neonatal cephalohematoma (aOR = 0.48, 95% CI 0.28-0.83) and admissions to intensive care nursery (aOR = 0.70, 95% CI 0.49-0.99) compared to operative vaginal deliveries during 1-3 h of second stage.
CONCLUSION: Compared to nulliparas who had operative vaginal deliveries performed early (1-3 h) in the second stage, women who delivered later (>3 h duration of second stage), either by spontaneous or operative vaginal delivery, had lower risk of third or fourth degree perineal lacerations without incurring risk of increased adverse neonatal outcomes.