Prospective Randomized Study of Oxytocin Discontinuation After the Active Stage of Labor is Established

Abstract

Prolonged episodes of labor induction or augmentation with oxytocin may make induction less effective and increase the risk of complications. This prospective study enrolled 342 pregnant women having labor induced, and randomly assigned them to either continue on oxytocin until the time of delivery (n = 174) or to stop receiving oxytocin at the start of the active phase of labor, defined as 5 cm of cervical dilation and regular contractions at 3-minute intervals (n = 168). All participants had a live fetus in cephalic presentation and an ultrasound-estimated fetal weight of less than 4000 g. Induction was carried out for a variety of reasons at 37–42 weeks' gestation. The 2 treatment groups did not differ significantly in maternal age, gestational age, incidence of nulliparity, or indications for induction. Both the duration of the active phase of labor and the length of the second stage were longer in the oxytocin-discontinued group, but the differences between groups were not statistically significant. Uterine hyperstimulation, based on 6 or more contractions in 10-minute intervals, was observed significantly more often in the oxytocin-continued group (P < 0.05). The overall rates of cesarean delivery were 6.9% for women in the oxytocin-continued group and 4.8% in the oxytocin-discontinued group (P > 0.05). In both groups, the indications for cesarean delivery were fetal distress and nonprogressive labor. No significant group differences in birth weight or signs of fetal distress were noted. These findings show that discontinuing oxytocin infusion once active labor is established is both effective and safe. This approach may be especially useful in developing countries where the conditions for fetal monitoring and emergency cesarean delivery are less readily available.