<b>Timing of carbetocin administration in vaginal deliveries: a double-blind, randomized controlled trial</b>

Abstract Background: Postpartum hemorrhage (PPH) remains a major cause of maternal morbidity and mortality. Carbetocin is recommended as an effective agent for the prevention PPH, but there is no generally accepted consensus on when to administer it. Objective: To compare the efficacy of administering carbetocin before versus after placental delivery in preventing PPH in low-risk vaginal deliveries. Methods: The randomized controlled trial was conducted at Kartal City Hospital, Istanbul, Turkey. A total of 160 primiparous women with uncomplicated pregnancies who underwent vaginal delivery were enrolled. Participants were randomly assigned to receive 100 mcg of carbetocin either before or after placental delivery. The primary outcome was the incidence of PPH, defined as blood loss ≥500 mL. Secondary outcomes included the need for additional uterotonics, antibiotics, blood transfusions, manual removal of the placenta, maternal adverse events, and changes in hemoglobin levels at baseline and 24 hours postpartum. Results: The carbetocin-before group had a significantly lower mean hemoglobin drop (0.76 ± 0.47 g/dL) compared to the carbetocin-after group (1.30 ± 0.61 g/dL) (p &lt;0.001). The need for additional uterotonics was significantly higher in the carbetocin-after group (p &lt;0.001). Manual placenta removal and the need for antibiotics were more frequent in the carbetocin-before group (10% vs. 1.3%, p = 0.017). No significant differences in adverse maternal events were observed between the groups. Discussion: Administering carbetocin before placental delivery significantly reduces blood loss and the need for additional uterotonics. However, the increased rate of manual placenta removal suggests that carbetocin should be administered in high-risk cases for PPH.