Association between oxytocin discontinuation during active labor and occiput posterior rotation at birth

OBJECTIVE: Oxytocin is commonly used in occiput posterior (OP) positions based on the assumption that it promotes rotation to the occiput anterior (OA) position, although supporting evidence is lacking. We compared OP-to-OA rotation at birth among women in whom oxytocin was discontinued versus continued during active labor. METHODS: This secondary subgroup analysis of a multicenter randomized controlled trial originally designed to evaluate the effect of discontinuing oxytocin during active labor on neonatal morbidity included women with a fetus in OP position at 6-cm cervical dilation. The rate of OA position at birth was compared between women allocated to discontinuation versus continuation of oxytocin during the active phase of the first stage of labor. A subgroup analysis excluded manual rotation attempts. Determinants of fetal head rotation were assessed using multilevel logistic regression. RESULTS: Among 344 women with a fetus OP position at 6-cm dilation, baseline characteristics were comparable between groups, and treatment contrast was maintained. OA position at birth occurred in 93.7% of women in the discontinuation group versus 88.3% in the continuation group (P = 0.08). After excluding manual rotations, OA position at birth was more frequent in the discontinuation group (97.8% vs. 90.2%; P < 0.01). Occiput transverse position (adjusted odds ratio [aOR] 8.71, 95% confidence interval [CI] 1.38-54.9) and gestational weight gain <12 kg (aOR 4.49, 95% CI 1.42-14.2) were independently associated with rotation. CONCLUSION: Discontinuation of oxytocin during active labor was not associated with a higher rate of persistent OP position at birth. These findings do not support routine continuation of oxytocin to promote fetal head rotation.