Oxytocin Bolus Matches Infusion for Uterine Tone, Reduces Blood Loss in Elective Cesarean

Despite oxytocin being the most widely used uterotonic for postpartum hemorrhage (PPH) prevention, high-quality data comparing bolus versus continuous infusion administration are limited. Given the very high uterine blood flow at term, rapidly achieving adequate uterine tone is critical to minimize blood loss during cesarean delivery. This trial aimed to address this knowledge gap by comparing these two common oxytocin administration methods.

This randomized, double-blinded clinical trial enrolled 121 patients undergoing elective cesarean delivery under spinal anesthesia. Patients were randomized 1:1 to receive either oxytocin bolus or oxytocin infusion immediately after cord clamping. Masked study drugs ensured blinding of all personnel. The primary endpoint was adequate uterine tone at 2 minutes. Secondary endpoints included patient satisfaction, time to adequate uterine tone, quantitative blood loss, postpartum hemorrhage (blood loss > 1000 mL), and safety measures (heart rate, blood pressure, phenylephrine dose, nausea/vomiting).

Of 121 patients enrolled, 115 were analyzable, with 114/115 receiving oxytocin per protocol. Baseline characteristics were similar between groups. The primary endpoint, adequate uterine tone at 2 minutes, was similar in the bolus group (50/60, 83.3%) versus the infusion group (43/55, 78.2%), with P = .483. Patient satisfaction scores also showed no significant difference (P = .495), with both arms reporting median scores of 10 (IQR 10-10).