Carbetocin versus oxytocin with or without tranexamic acid for preventing postpartum hemorrhage in cesarean delivery: a randomized controlled trial

Postpartum hemorrhage (PPH) is a significant contributor to maternal morbidity, particularly following cesarean deliveries. Uterotonics, including oxytocin and carbetocin, are commonly used to prevent PPH. However, the comparative effectiveness of these agents when used in conjunction with tranexamic acid remains uncertain. This study aims to evaluate the efficacy of carbetocin, oxytocin, and their combinations with tranexamic acid in mitigating intraoperative blood loss during cesarean deliveries. In this randomized, double-blind, two-factorial trial, 200 women scheduled for cesarean sections were allocated into four groups (n = 50 each): carbetocin (100 µg), carbetocin combined with tranexamic acid, oxytocin (5 IU), and oxytocin combined with tranexamic acid. The interventions were administered intravenously immediately after delivery. The primary outcome was estimated intraoperative blood loss in the first 24 h, assessed through suction volume and gauze counts. Secondary outcomes included hematological parameters (hemoglobin, hematocrit) and hemodynamic changes (blood pressure, heart rate). The carbetocin group demonstrated significantly lower blood loss (629.0 ± 139.62 mL) compared to the oxytocin plus tranexamic acid group (712.7 ± 131.32 mL; p = 0.017). Post-hoc analysis revealed no significant difference in blood loss between the carbetocin and oxytocin-alone groups. Carbetocin also resulted in the smallest decreases in hematocrit (-2.01%) and hemoglobin (-0.99 g/dL), along with minimal changes in blood pressure (+ 1.60 mmHg systolic, + 3.42 mmHg diastolic). In contrast, the oxytocin groups exhibited greater hemodynamic fluctuations, characterized by significant reductions in blood pressure and increases in heart rate (p < 0.001). Significant differences in hematocrit, white blood cell count, and blood pressure changes were observed between the groups (p < 0.05). No significant differences in adverse effects were identified among the groups. In this trial, carbetocin was associated with less blood loss than oxytocin combined with tranexamic acid and demonstrated a more favorable hemodynamic profile compared to oxytocin-based regimens. These findings suggest it may be considered a preferred uterotonic agent for the prevention of PPH in cesarean deliveries, though the role of tranexamic acid requires further clarification.