Carbetocin doses from 20 μg to 100 μg show similar PPH prevention efficacy in elective C-sections

Postpartum haemorrhage (PPH) remains a leading cause of maternal morbidity and mortality globally, often stemming from uterine atony. Current standard-of-care uterotonics, like oxytocin, are effective but can have variable responses and side effects. Carbetocin, a long-acting oxytocin analog, is widely used for PPH prophylaxis, particularly during caesarean delivery, with a standard dose of 100 μg. However, the optimal effective dose to achieve adequate uterine tone and minimize adverse effects, while potentially reducing cost, has not been definitively established, leaving a gap in evidence-based dosing protocols.

Researchers conducted a randomized, parallel-group, dose-response trial involving 100 low-risk, non-obese parturients undergoing elective caesarean delivery under spinal anaesthesia. Participants were assigned to five groups (n = 20 per group) to receive intravenous carbetocin at doses of 100 μg, 80 μg, 60 μg, 40 μg, or 20 μg immediately after foetal delivery. The primary outcome was satisfactory uterine tone assessed at 2, 5, and 10 minutes. Secondary outcomes included mean blood loss, requirement for additional uterotonics, PPH incidence, blood transfusion, haemodynamic variables, and adverse events. Trend analysis was used to evaluate dose-response relationships.

Baseline demographic and obstetric characteristics were comparable across all five dose groups. Uterine contraction progressively improved over time, with 75-85% of women achieving satisfactory tone at 2 minutes, increasing to 90-95% at 5 minutes, and 95-100% at 10 minutes. Crucially, no significant intergroup differences in uterine tone were observed at any time point (P = 0.960 at 2 min, P = 0.921 at 5 min, and P = 0.724 at 10 min). Mean blood loss, the requirement for additional uterotonics, the incidence of PPH, the need for blood transfusion, haemodynamic variables, and adverse events were all found to be comparable across the entire dose range. No statistically significant dose-response relationship was identified for any of the measured outcomes. This suggests that lower doses of carbetocin may be as effective as the standard 100 μg dose.

Intravenous carbetocin doses ranging from 20 μg to 100 μg resulted in similar uterotonic response and blood-loss outcomes, with no statistically significant differences between the different dose groups.