A Randomised Controlled Trial of Early Versus Delayed Oxytocin Augmentation to Treat Primary Dysfunctional Labour in Nulliparous Women

Abstract

Primary dysfunctional labor, the most common indication for caesarean section, accounts for 30% of caesarean births, and is primarily a problem in nulliparous women. Oxytocin has been widely used to hasten labor in such women, but there is little or no data in randomized trials of sufficient sample size to support the contention that oxytocin reduces the need for caesarean section. In this unblinded prospective randomized controlled trial, 412 low-risk nulliparous women with primary dysfunctional labor were assigned to receive either immediate oxytocin administration (active group, n = 208) or oxytocin withheld for up to 8 hours (control group, n = 204). Neither obstetricians nor participants were blinded to the treatment group. Baseline characteristics were similar in both groups. The Edinburgh Postnatal Depression Scale (EPDS) assessed the rate of maternal major depression within 48 hours of delivery through use of a questionnaire. Early oxytocin produced no significant reduction in caesarean section rates (13.5% active versus 13.7% controls (odds ratio [OR] 0.98, 95% confidence interval [CI] 0.6-1.7), but shortened labor by over 3 hours (active group: 5 hours 52 minutes (3:57-8:28) versus control group 9 hours 8 minutes (5:06-13:16) [P <.001]). Early use may also reduce the rate of operative vaginal delivery (24.5% active versus 30.9% controls, OR 0.73, 95% CI 0.5-1.1). Early oxytocin did not reduce short-term postnatal depression nor was there any significant difference between the treatment groups in maternal or neonatal complications. One perinatal death occurred in each group. This is the largest randomized controlled trial published in full that supports early use of oxytocin to reduce the length of labor in nulliparous women with primary dysfunctional labor. The authors conclude from these findings that early oxytocin may reduce operative vaginal deliveries, but no support is provided for the contention that it reduces rates of caesarean section.