(244) Effect of a High Dose Oxytocin Protocol for Management of Labor

Objective: Randomized data suggest high dose oxytocin reduces duration of labor without increasing adverse outcomes. Among nulliparous patients without contraindications to labor, we compared low versus high dose oxytocin on rate of spontaneous vaginal delivery (SVD) within 24 hours of oxytocin initiation.

Study Design: We conducted a retrospective cohort study of nulliparous women 36w0d gestation or greater undergoing labor induction or augmentation at a single tertiary care center from April 2021 to August 2023. Patients with a history of uterine surgery or non-cephalic presentation were excluded. Low dose oxytocin protocol was standard of care prior to September 2022 and consisted of a starting dose of 2 mU/minute, titrated by 2 mU/minute every 30 minutes. Patients delivering after September 2022 received high dose oxytocin protocol, which consisted of a starting dose of 4 mU/minute, titrated by 4 mU/minute every 30 minutes. Primary outcome was SVD within 24 hours of oxytocin initiation. Secondary outcomes included median duration of labor, delivery mode, intra-amniotic infection (IAI), postpartum hemorrhage (PPH), and five-minute Apgar less than 7.

Results: There were 2,147 patients eligible for enrollment: 1058 in the low dose oxytocin arm and 1089 in the high dose oxytocin arm. There was no difference in rate of SVD within 24 hours according to oxytocin dose protocol (69 vs 67%, p 0.381). Similarly, there were no differences in secondary outcomes. A sub-analysis was performed to assess patients who received oxytocin alone without exposure to other methods of induction or augmentation. Rate of SVD within 24 hours increased (81 vs 75%, p 0.048) and labor duration decreased (10.5 vs 12.7 hours, p < 0.001) with high dose oxytocin when compared to low dose oxytocin.

Conclusion: When assessing all nulliparous patients admitted for labor induction or augmentation, implementation of a high dose oxytocin protocol did not result in increased rates of SVD within 24 hours. Rates of SVD within 24 hours were increased and median labor duration was shorter with oxytocin exposure alone.