News Release

Thursday, April 13, 2023

Tranexamic acid does not appear to prevent maternal hemorrhage after cesarean delivery

Tranexamic acid appears no more effective than placebo in reducing the need for blood transfusion or preventing maternal death in patients with increased risk for excessive bleeding because of cesarean delivery, according to a study funded by the National Institutes of Health. Tranexamic acid slows the natural breakdown of blood clots and was considered promising for reducing the risk of excessive bleeding after giving birth—known as postpartum hemorrhage—after cesarean delivery.

In addition, patients who received tranexamic acid had slightly less need for additional medical or surgical interventions to treat postpartum hemorrhage and a slightly lower drop in red blood cell count.

The study was led by Luis D. Pacheco, M.D., of the University of Texas Medical Branch at Galveston, and colleagues. It appears in the New England Journal of Medicine. Funding was provided by NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD).

“Our findings differ from those of previous trials, which were smaller and therefore did not have the statistical power to detect a difference in the need for blood transfusion between groups,” said study author Monica Longo, M.D., of the NICHD Pregnancy and Perinatology Branch. “The current study included participants from 31 birthing centers across the United States and found no benefit of the drug, compared to placebo.”

Previously, researchers have theorized that since tranexamic acid prevents the breakdown of blood clots, the drug might slow blood loss and reduce the risk of postpartum hemorrhage. Tranexamic acid has been found to be effective among women experiencing postpartum hemorrhage. Researchers sought to determine the effectiveness of the drug for patients undergoing cesarean delivery who did not have hemorrhaging at the time of treatment.

Researchers assigned 11,000 patients to receive either intravenous tranexamic acid or placebo after umbilical cord clamping at the time of cesarean delivery. The study included women who had undergone scheduled and unscheduled cesarean delivery.

The researchers reported the results as a single primary outcome of events that might be expected with postpartum hemorrhage, the need for a transfusion of red blood cells or death. These events occurred in 201 patients (3.6%) in the tranexamic acid group and 233 (4.3%) in the placebo group, a difference that was not statistically significant. For the placebo group, one death occurred. There were no deaths in the tranexamic acid group. There was no significant difference between the groups for the secondary outcome of estimated blood loss of more than 1 liter during the procedure: 7.3% in the tranexamic acid group, 8% in the placebo group.

However, the study found that patients who received tranexamic acid had less need for additional medical or surgical interventions to treat postpartum hemorrhage, compared to the placebo group (16.1% versus 18%), and a lower drop in red blood cell count after cesarean delivery (1.8 grams per deciliter versus 1.9 grams per deciliter).

The tranexamic acid group was more likely to have an infection after giving birth, 3.2% to 2.5%. The authors noted that previous trials had not seen a difference in infection rates between the groups and added that the finding would need to be confirmed by additional research.

About the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD): NICHD leads research and training to understand human development, improve reproductive health, enhance the lives of children and adolescents, and optimize abilities for all. For more information, visit https://www.nichd.nih.gov.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

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