Tranexamic Acid for the Prevention of Blood Loss after Vaginal Delivery

BACKGROUND The use of tranexamic acid reduces mortality due to postpartum hemorrhage. We investigated whether the prophylactic administration of tranexamic acid in addition to prophylactic oxytocin in women with vaginal delivery would decrease the incidence of postpartum hemorrhage. METHODS In a multicenter, double-blind, randomized, controlled trial, we randomly assigned women in labor who had a planned vaginal delivery of a singleton live fetus at 35 or more weeks of gestation to receive 1 g of tranexamic acid or placebo, administered intravenously, in addition to prophylactic oxytocin after delivery. The primary outcome was postpartum hemorrhage, defined as blood loss of at least 500 ml, measured with a collector bag. RESULTS Of the 4079 women who underwent randomization, 3891 had a vaginal delivery. The primary outcome occurred in 156 of 1921 women (8.1%) in the tranexamic acid group and in 188 of 1918 (9.8%) in the placebo group (relative risk, 0.83; 95% confidence interval [CI], 0.68 to 1.01; P = 0.07). Women in the tranexamic acid group had a lower rate of provider-assessed clinically significant postpartum hemorrhage than those in the placebo group (7.8% vs. 10.4%; relative risk, 0.74; 95% CI, 0.61 to 0.91; P = 0.004; P = 0.04 after adjustment for multiple comparisons post hoc) and also received additional uterotonic agents less often (7.2% vs. 9.7%; relative risk, 0.75; 95% CI, 0.61 to 0.92; P = 0.006; adjusted P = 0.04). Other secondary outcomes did not differ significantly between the two groups. The incidence of thromboembolic events in the 3 months after delivery did not differ significantly between the tranexamic acid group and the placebo group (0.1% and 0.2%, respectively; relative risk, 0.25; 95% CI, 0.03 to 2.24). CONCLUSIONS Among women with vaginal delivery who received prophylactic oxytocin, the use of tranexamic acid did not result in a rate of postpartum hemorrhage of at least 500 ml that was significantly lower than the rate with placebo.