Does Increased Time Off Oxytocin Decrease Blood Loss at the Time of Cesarean Birth? [14M

Abstract

INTRODUCTION: Prolonged periods of oxytocin use during labor can lead to higher rates of postpartum hemorrhage due to oxytocin receptor desensitization. We aimed to determine whether increased time off oxytocin prior to cesarean birth decreased the rate of quantified blood loss (QBL). METHODS: This is a retrospective cohort study of women with singleton pregnancies receiving at least 4 hours of oxytocin and delivering via cesarean at the University of California, San Francisco from May 2018 to June 2019. The primary exposure was the time off oxytocin to delivery, in minutes. The primary outcome was QBL, in milliliters. Secondary outcomes included need for blood transfusion, additional uterotonics, additional surgeries needed, and change in hemoglobin. RESULTS: 338 patients had a cesarean birth after exposure to oxytocin. The mean time from stopping oxytocin to delivery was 119 minutes (IQR 62-133 minutes). The average QBL was 1179 mL (IQR 770-1492 mL). There was no significant difference in QBL based on time off oxytocin (-4.0 mL per 10 min, 95% CI −9.5 to +1.4 mL). There was an increased risk of blood transfusion in those off oxytocin for fewer than 2 hours versus more than 2 hours (14.0% vs. 4.6%, P=.010). This finding persisted after controlling for age, BMI, stage of labor, admission hemoglobin, chorioamnionitis and cumulative oxytocin dose (aOR 2.97, 95% CI 1.06-8.23). CONCLUSION: We did not find an association between time off oxytocin before delivery and QBL. However, there was an increased risk of blood transfusion among those off oxytocin for less than 2 hours.