Low-dose Oxytocin Protocol Makes No Difference in Quantitative Blood Loss in Elective Cesarean Sections; a Single-Center, Retrospective Cohort Study

Abstract Background The prophylactic use of oxytocin after fetal delivery has been shown to reduce maternal blood loss by 40–50%, yet there remains significant clinical deviation in how the medication is dosed. In January, 2021, the Defense Health Agency (DHA) issued Procedural Instruction 6025.35 entitled Guidance for Implementation of the Postpartum Hemorrhage Bundle. This directive established a set of processes and procedures for the risk assessment and treatment of postpartum hemorrhage (PPH), including a new standardized oxytocin protocol for vaginal and cesarean deliveries. Methods This single-center, retrospective cohort study compared quantitative blood loss in healthy parturients undergoing elective cesarean sections that received either unmeasured, high-dose oxytocin (40 IU) or a low-dose oxytocin protocol (3 IU bolus followed by 18 IU per hour) using a multivariate linear regression model. Results After controlling for patient age, gestational age at time of delivery, cesarean section indication, and hemorrhagic medications given, the multivariate linear regression model found the regimen of oxytocin a patient received was not predictive of their blood loss (R² = 0.08, adjusted R² of -0.003, p = 0.48). Additionally, the low-dose group had less blood loss by estimated marginal means (944mL, 95% CI 724–1164, versus 769mL, 95% CI 526–1011). Conclusions This study suggests the low-dose oxytocin protocol released in the Defense Health Agency hemorrhage bundle is safe and effective with regards to preventing blood loss from uterine atony, and should be adopted by all military treatment facilities.