Double-blind comparison of carbetocin versus oxytocin in preventing uterine atony post cesarean section

Objectives : The aim of this study was to compare carbetocin, a long-acting oxytocin analog, to oxytocin in the prevention of post-cesarean uterine atony. Material and methods : We enrolled 694 patients going for elective repeat cesarean in a Canadian multicentre double-blind randomized clinical trial. We compared the effect of a single dose of carbetocin (100 mcg.IV) to a standard 8 h IV infusion of oxytocin. The primary outcome was the proportion of patients requiring additional uterotonic drugs. The design used a sequential analysis using the double triangular test. Results : The overall uterotonic intervention rate was 7.4%. The odds of treatment failure was 2.0 times higher in the oxytocin group compared with the carbetocin group (respectively 10.1% vs. 4.7%, P<0.05). Interim safety analysis shows carbetocin to be well tolerated with a safety profile similar to oxytocin. Conclusion : Carbetocin, a new drug to prevent uterine atony, appears to be more effective than a continuous infusion of oxytocin in preventing uterine atony post-Cesarean.