Heat stable carbetocin or oxytocin for prevention of postpartum hemorrhage among women at risk: A secondary analysis of the CHAMPION trial

Objective: To examine whether the observed non-inferiority of heat-stable carbetocin (HSC), compared with oxytocin, was influenced by biologic (macrosomia, parity 3 or more, or history of postpartum hemorrhage [PPH]) and/or pharmacologic (induction or augmentation) risk factors for PPH. Methods: The present study is a secondary analysis of the CHAMPION non-inferiority randomized trial—a two-arm, double-blind, active-controlled study conducted at 23 hospitals in 10 countries, between July 2015 and January 2018. Women with singleton pregnancies, expected to deliver vaginally with cervical dilatation up to 6 cm were eligible. Randomization was stratified by country, with 1:1 assignment. Women in the intervention and control groups received a single intramuscular injection of 100 μg of HSC or 10 IU of oxytocin, respectively. The drugs were administered immediately after birth, and the third stage of labor was managed according to the WHO guidelines. Blood was collected using a plastic drape. For this analysis, we defined a woman as being at risk if she had any one or more of the biologic or pharmacologic risk factor(s). Results: The HSC and oxytocin arms contained 14 770 and 14 768 women, respectively. The risk ratios (RR) for PPH were 1.29 (95% confidence interval [CI] 1.08–1.53) or 1.73 (95% CI 1.51–1.98) for those with only biologic (macrosomia, parity 3 or more, and PPH in the previous pregnancy) or only pharmacologic (induced or augmented) risk factors, respectively, compared with those with neither risk factors. Conclusions: Findings reinforce previous evidence that macrosomia, high parity, history of PPH, and induction/augmentation are risk factors for PPH. We did not find a difference in effects between HSC and oxytocin for PPH among women who were neither induced nor augmented or among those who were induced or augmented.