Tranexamic acid use before CS reduces blood loss

The use of prophylactic tranexamic acid (TXA) prior to elective Caesarean section (CS) led to significantly lower blood loss in women, particularly those at high risk for postpartum haemorrhage (PPH), according to a study presented at RCOG 2023.

“PPH remains one of the leading causes of maternal morbidity and accounts for more than a quarter of maternal deaths worldwide,” said lead author Dr Shi Hui Lee from the Department of Obstetrics and Gynaecology at KK Women’s and Children’s Hospital in Singapore.

“The World Health Organization recommends prophylactic uterotonics such as oxytocin to prevent PPH … However, PPH is unpredictable, and majority of cases occur in the absence of risk factors,” the researchers said in a recently published paper. [BJOG 2023;00:1-9]

Hence, the researchers conducted a single-centre, double-blind, placebo-controlled trial involving 200 women (aged ≥21 years) undergoing elective CS. Participants were randomized in a 1:1 ratio to receive either intravenous TXA 1 g or placebo (normal saline 10 mL), 10 minutes before skin incision. All participants were also given intravenous oxytocin 5U after delivery as per routine practice. The primary outcome of the study was calculated estimated blood loss (cEBL), which was derived from estimated blood volume and change in preoperative and postoperative haematocrit.

In the intention-to-treat analysis, patients treated with TXA had a significantly lower blood loss than those treated with placebo (mean cEBL, 620.6 vs 754.1 mL; adjusted mean difference of -126.4 mL; p=0.035).

Notably, the reduction in cEBL was even greater in patients at high risk for PPH who received TXA compared to those receiving placebo (mean difference, -279.6 mL; p=0.002).

There was also a significantly lower risk of PPH among TXA recipients with a cEBL of ≥500 mL (risk ratio [RR], 0.54; p=0.007) or ≥1,000 mL (RR, 0.44; p=0.016) than placebo recipients.

With regard to secondary outcomes, the need for additional medical interventions, such as additional uterotonics (50.0 percent vs 53.1 percent) or TXA (8.3 percent vs 8.2 percent), did not differ between the TXA and placebo groups.

At approximately 48 hours post-delivery, patients who received TXA experienced a significantly lower percentage drop in haemoglobin than those who received placebo (-9.6 percent vs -12.4 percent; p=0.018), but there was no significant difference in the need for blood transfusions between the two groups.

In a subgroup analysis, patients with maternal anaemia, defined as preoperative haemoglobin of <10.5 g/dL, had a significant reduction in cEBL with TXA compared with placebo (mean difference, -281.9 mL; p=0.019). “This is an important finding given that maternal anaemia is common in Asian women,” the researchers said.

Lee noted that the findings of this study were consistent with a previous trial (TRAPP2), which demonstrated that TXA reduced the risk of PPH, with a mean difference in EBL of -107 mL. [N Engl J Med 2021;384:1623-1634]

“Overall, TXA significantly reduced blood loss compared with placebo … The effect was greatest among women at high risk for PPH, with TXA significantly reducing cEBL … and the risk of PPH,” Lee concluded.