Second-Line Uterotonics in Postpartum Hemorrhage: A Randomized Clinical Trial

Primary postpartum hemorrhage (PPH) is defined by the American College of Obstetricians and Gynecologists as a cumulative blood loss of >1000 mL within 24 hours of the birth process. PPH remains a leading source of maternal morbidity and mortality worldwide with uterine atony identified as the underlying cause in up to 80% of cases. Between 1994 and 2006, the rate of PPH increased by 26% in the United States, raising further concern for this problem.

Treatment of PPH typically begins with administration of exogenous oxytocin, a hormone responsible for uterine contraction. When postpartum bleeding persists despite oxytocin administration, a multidisciplinary approach combining mechanical, pharmacologic, and surgical measures is indicated. Approximately 3-25% of PPH cases require a second-line uterotonic agent in addition to oxytocin, with the two most commonly administered second-line agents in the U.S.A. being methylergonovine maleate (methylergonovine) and 15-methyl prostaglandin F2α (carboprost). The comparative efficacy of these two drugs is unknown and the most recent American College of Obstetricians and Gynecologists Practice Bulletin makes no recommendation on which second-line uterotonic agents to administer preferentially in the absence of contraindications.

This study will evaluate in a randomized fashion the comparative efficacy of methylergonovine and carboprost for treating atonic PPH. Patients undergoing non-emergent cesarean section (C/S) with uterine atony and no contraindications to either drug will be randomized to receive one of the two equivalent agents in a blinded fashion after oxytocin. After ten minutes, their uterine tone will be assessed by the obstetrician and reported on a 0-10 point scale.

A power calculation was performed to detect a mean difference in uterine tone between groups of 1 point on a 0-10 point scale with 80% power and significance level of 0.05. The investigators estimate 37 patients will be required in each arm. Allowing for a 20% rate of withdrawals or missing information, a total of 100 patients will be enrolled in this study.

Investigators will adhere to the FDA Expedited Safety Requirements in reporting any adverse event that is serious, unexpected, and associated with the use of the study drugs. Any such adverse event will be reported to the study site Institutional Review Board (IRB) and serious events will prompt the study to be halted until further discussion with the IRB.