Augmentation of labour with oxytocin and its association with delivery outcomes: a large-scale cohort study in 12 public hospitals in Nepal.

INTRODUCTION: The use of oxytocin to augment labour is increasing in many low-resource settings, however, little is known about the effects of such use in contexts where resources for intrapartum monitoring are scarce. In this study, we sought to assess the association between augmentation of labour with oxytocin and delivery outcomes. MATERIAL AND METHODS: We conducted a cohort study in 12 public hospitals in Nepal, including all deliveries with and without augmentation of labour with oxytocin, but excluding elective cesarean sections, women with missing information on augmentation of labour, and women without fetal heart rate on admission. Bivariate and multivariate logistic regression calculating the crude and adjusted risk ratio (aRR) with corresponding 95% confidence intervals (CI) were performed, comparing 1) intrapartum stillbirth and first-day mortality (primary outcome), and 2) intrapartum monitoring, mode of delivery, post-partum hemorrhage, bag-and-mask ventilation of the newborn, Apgar score, and neonatal death before discharge (secondary outcomes) among women with and without oxytocin-augmented labour. RESULTS: The total cohort consisted of 78 931 women of which 28 914 (37%) had labour augmented with oxytocin and 50 016 (63%) did not have labour augmented with oxytocin. Women with augmentation of labour had no increased risk of intrapartum stillbirth and first-day mortality (aRR 1.24, 95% CI 0.65-2.4), but a decreased risk of suboptimal partograph use (aRR 0.71, 95% CI 0.68-0.74), a decreased risk of suboptimal fetal heart rate monitoring (aRR 0.50, 95% CI 0.48-0.53), a decreased risk of emergency cesarean section (aRR 0.62, 95% CI 0.59-0.66), an increased risk of bag-and-mask ventilation (aRR 2.1, 95% CI 1.8-2.5), an increased risk of Apgar score < 7 at 5 minutes (aRR 1.65, 95% CI 1.49-1.86), and a an increased risk of neonatal death (aRR 1.93, 95% CI 1.46-2.56). CONCLUSIONS: Although augmentation of labour with oxytocin might be associated with beneficial effects such as improved monitoring and a decreased risk of caesarean section, its use may lead to an increased risk of adverse perinatal outcomes. We urge for a cautious use of oxytocin to augment labour in low-resource contexts, and call for evidence-based guidelines on augmentation of labour in low-resource settings.