Tranexamic acid prevents blood loss after cesarean delivery
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Treatment with tranexamic acid significantly reduced the incidence of calculated estimated postpartum blood loss of more than 1000 mL or red‐cell transfusions within 2 days of cesarean delivery, according to a randomized controlled trial.
However, tranexamic acid did not reduce the incidence of hemorrhage-related secondary clinical outcomes — a surprising finding, researchers said.
“In fact, all meta-analyses of summary data of small single‐center, randomized controlled trials have shown that tranexamic acid administration at cesarean delivery resulted in significantly less mean gravimetrically estimated blood loss as well as in less frequent blood loss exceeding 500 mL and 1000 mL, less frequent use of additional uterotonic agents, and fewer transfusions than placebo or no treatment,” study author Loïc Sentilhes, MD, PhD, of the department of obstetrics and gynecology at Bordeaux University Hospital in France, told Healio Primary Care.
“Nevertheless, meta-analyses of small trials are prone to biases, especially publication bias,” Sentilhes continued. “Positive findings in small trials are often not substantiated by subsequent large, randomized trials.”
The multicenter, double-blind, randomized controlled trial included 4,153 women who were at least 34 weeks pregnant and undergoing cesarean delivery. All women in the study received prophylactic uterotonic agents intravenously. Approximately half (n = 2,085) were randomly assigned to receive additional treatment with 1 g of tranexamic acid, and the rest received a placebo. Women with hemoglobin levels of less than 9 g per dL were not included “to reduce the likelihood of postpartum transfusion in the absence of clinically significant blood loss,” according to the researchers.
Sentilhes and colleagues reported in The New England Journal of Medicine that 26.7% of the women in the tranexamic acid cohort and in 31.6% of those who received a placebo experienced postpartum hemorrhage (adjusted RR = 0.84; 95% CI, 0.75-0.94) — defined as an estimated blood loss exceeding 1000 mL or receipt of a red-cell transfusion within 2 days of delivery. The mean between-group difference was approximately 100 mL, and likely stemmed from “a significantly smaller decrease in hematocrit from before surgery to after surgery in the tranexamic acid group than in the placebo group,” according to the researchers.
The findings are the first to show “with a high level of evidence that tranexamic acid prevents blood loss after a cesarean delivery,” Sentilhes said.
However, the researchers questioned the clinical relevance of their finding, since there were no significant between-group differences in the secondary clinical outcomes — mean number of gravimetrically estimated blood loss or in the percentage of women with provider-assessed clinically significant postpartum hemorrhage, use of additional uterotonic agents or postpartum blood transfusion.
Perspective
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This is a well-designed study with the aim of answering important obstetrical question.
We know that tranexamic acid is effective in the treatment of hemorrhage, and we know that women are at high risk for hemorrhage at the time of c-section. It would be ideal if we could use tranexamic acid to prevent hemorrhage in the first place rather than scrambling to fix a hemorrhage that is well underway. This is exactly what Sentilhes and colleagues investigated with this project.
Their work produced some interesting positive findings, most notably the statistically significant decreases in quantity of blood loss and in occurrence of blood loss greater than 1000 mL in the tranexamic acid group compared with the placebo group. However, when looking at their secondary outcomes, this difference does not appear to correlate with any significant difference in clinically relevant outcomes like incidence of blood transfusion, ICU admission or emergency surgery for hemorrhage. Additionally, the group that received tranexamic acid reported a significantly higher incidence of perioperative nausea, vomiting and dizziness than the placebo group.
In the end, this study helps to support our knowledge that tranexamic acid does have a physiologic effect on quantity of blood lost but does not demonstrate that this decrease is meaningful enough to produce a change of any clinical relevance when used prophylactically at the time of cesarean delivery. Until a clinical improvement in patient outcome can be demonstrated, I believe that obstetricians should continue to reserve the use of tranexamic acid during c-sections for the treatment of active bleeding rather than for prophylactic bleeding prevention.
Assistant professor, department of obstetrics and gynecology, Virginia Commonwealth University
Perspective
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Tranexamic acid was already a critical part of the armamentarium of medications that can be provided to women who are hemorrhaging in the immediate postpartum period to help reduce the amount of blood loss. These new findings indicate another use for this therapeutic agent: we can prophylactically give something to our patients immediately before birth to help reduce the incidence of blood loss and postpartum hemorrhage.
Here at Mercy Medical Center during the past few years, we have seen an increase in blood loss during cesarean sections and a continual increase in the amount of blood transfusions being administered to our patients giving birth via this procedure. Therefore, the results by Sentilhes and colleagues is good news.
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