Impact of discontinuing oxytocin in active labour on neonatal morbidity: an open-label, multicentre, randomised trial

Background Oxytocin is effective in reducing labour duration but can be associated with fetal and maternal complications that could potentially be reduced by discontinuing the treatment during labour. We aimed to assess the impact of discontinuing oxytocin during active labour on neonatal morbidity. Methods STOPOXY was a multicentre, randomised, open-label, controlled, superiority trial conducted in 21 maternity units in France. Participants who received oxytocin before 4 cm dilation were randomly assigned 1:1 to either discontinuous oxytocin (oxytocin infusion stopped beyond a cervical dilation equal to or greater than 6 cm) or continuous oxytocin (administration of oxytocin continued until delivery). Randomisation was stratified by centre and parity. The primary outcome, neonatal morbidity, was assessed at birth using a composite variable defined by an umbilical arterial pH at birth less than 7 center dot 10, a base excess greater than 10 mmol/L, umbilical arterial lactates greater than 7 mmol/L, a 5-min Apgar score less than 7, or admission to the neonatal intensive care unit. Efficacy and safety was assessed in participants who were randomly assigned (excluding those who withdrew consent or were deemed ineligible after randomisation) and had reached a cervical dilation of at least 6 cm. This trial is registered with ClinicalTrials.gov, NCT03991091. Findings Of 2459 participants randomly assigned between Jan 13, 2020, and Jan 24, 2022, 2170 were eligible to receive the intervention and were included in the final modified intention-to-treat analysis. The primary outcome occurred for 102 (9 center dot 6%) of 1067 participants (95% CI 7 center dot 9 to 11 center dot 5) in the discontinuous oxytocin group and for 101 (9 center dot 2%) of 1103 participants (7 center dot 6 to 11 center dot 0) in the continuous oxytocin group; absolute difference 0 center dot 4% (95% CI -2 center dot 1 to 2 center dot 9); relative risk 1 center dot 0 (95% CI 0 center dot 8 to 1 center dot 4). There were no clinically significant differences in adverse events between the two groups of the safety population. Interpretation Among participants receiving oxytocin in early labour, discontinuing oxytocin when the active phase is reached does not clinically or statistically significantly reduce neonatal morbidity compared with continuous oxytocin. Funding French Ministry of Health and the Departement de la Recherche Clinique et du Developpement de l'Assistance Publique-Hopitaux de Paris. Copyright (c) 2023 Elsevier Ltd. All rights reserved.