Outcome of Early Versus Delayed Oxytocin Augmentation in Nulliparous Women on the Duration of Labour and other Obstetric and Neonatal Outcome - A Randomized Controlled Trial

Abstract

Objectives: To determine the outcome of early versus delayed Oxytocin augmentation in nulliparous women on the duration of labor and other obstetric and neonatal outcomes. Study Design:A prospective randomized trial. Place and Duration of study: The study was conducted at Pakistan Railways Hospital, for the duration of 1 year with effect from January 2010 January, 2011. It is 400 bedded teaching hospital affiliated with IIMC-T of Riphah International University, Islamabad Materials and Methods: In healthy nulliparous women with normal pregnancy,the progress of labor was thoroughly monitored and documented every 23 hours. If there was still no progress 1 hour after amniotomy, the woman was randomly allocated to either labor augmentation by oxytocin infusion or to postponement of oxytocin augmentation for 3 hours (expectant group, n = 158). Women whose labors had progressed satisfactory (1 cm/hour) after amniotomy were not randomized. Participants were managed according to a standard protocol entailing continuous documentation of the progress of labour, the amount of oxytocin administered, and obstetrical and neonatal outcomes. Oxytocin infusion was started at 6 mU/minute and was raised by 6 mU/minute every 30 minutes until efficient contractions were established in the early oxytocin group. In the expectant group, if no progress occurred after 3 hours, the women were reassessed regarding the need for oxytocin augmentation. Data were analyzed with SPSS 15.0. The MannWhitney U test was used to compare means. Proportions of events were compared with Fisher's exact test or chi-square analysis. Statistical significance was set at a Pvalue of <0.05. Results: The caesarean section rate was 9% in the early oxytocin group and 10.7% in the expectant group (OR 0.8, 95% CI 0.51.4), and instrumental vaginal delivery 17% in the early oxytocin versus 12% in the expectant group (OR 1.5, 95% CI 0.972.4). Early initiation of oxytocin resulted in a mean decrease of 85 minutes in the randomization to delivery interval. Conclusion: Early administration of oxytocin did not change the rate of caesarean section or instrumental vaginal delivery but shortened labor duration significantly in women with a 2-hour arrest in cervical dilatation. No other clear benefits or harms were seen between early and delayed administration of oxytocin.

Keywords

• oxytocin augmentation, prolonged labor, fetal distress.