Giving tranexamic acid to women with placenta praevia (when the placenta covers the cervical opening) undergoing caesarean birth leads to a significant yet modest reduction in severe bleeding after delivery with no evidence of an increase in serious adverse events, finds a trial from China.
Tranexamic acid is widely used to prevent or reduce heavy bleeding usually after surgery or trauma. It works by inhibiting blood clot breakdown and is recommended for the treatment of severe bleeding after childbirth (postpartum haemorrhage).
But high quality evidence on its prophylactic use to prevent postpartum haemorrhage in high risk women remains scarce. To address this gap, researchers in China set out to examine the effect of tranexamic acid in women with placenta praevia, a group at high risk of severe bleeding.
The trial included 1,694 pregnant women with placenta praevia who were scheduled for caesarean delivery at 24 maternity units across China between July 2023 and March 2025.
Participants received prophylactic oxytocin - standard treatment to reduce blood loss after delivery - and were randomly assigned to receive either intravenous tranexamic acid (845 women) or placebo (849 women) over 10 minutes, starting within five minutes of umbilical cord clamping.
The main outcome measure was postpartum haemorrhage, defined as blood loss of at least 1000 mL or red blood cell transfusion within two days after delivery. Serious adverse events including blood clots, seizures, acute kidney or liver injury, and maternal death, were also recorded.
The results show that prophylactic tranexamic acid reduced the rate of postpartum haemorrhage by 15%, from 35.1% to 29.7% compared with placebo. This means that for every 19 women receiving prophylactic tranexamic acid, one case of postpartum haemorrhage would be prevented.
Rates of serious adverse effects were similar between the two groups. The researchers acknowledge various limitations including that the findings are specific to women with placenta praevia receiving prophylactic oxytocin and therefore may not apply to other obstetric populations. However, this was a well-designed trial and results were consistent after further analyses, suggesting that the findings are robust.
As such, they conclude: “In a high risk population - specifically, women with placenta praevia undergoing caesarean delivery - prophylactic tranexamic acid leads to a statistically significant but modest reduction in the incidence of postpartum haemorrhage.”
“Future studies in diverse international settings are warranted to validate these results and to identify specific patient subgroups most likely to benefit from prophylactic use of tranexamic acid,” they add.
In a linked editorial, UK researchers point out that this modest reduction in bleeding understates the impact, particularly in women at high risk of harm from bleeding, for whom even modest relative risk reductions translate into worthwhile benefits.
The focus should now shift from whether tranexamic acid reduces bleeding to how it is used to maximise patient benefit, they say, noting that in non-obstetric surgery, tranexamic acid is given before incision, but in caesarean section trials it is delayed until after cord clamping to avoid placental transfer.
They recommend evaluating pre-incision administration for caesarean section, while carefully monitoring maternal and neonatal outcomes.
The paper, published by The BMJ, can be accessed at: Prophylactic tranexamic acid for the prevention of postpartum haemorrhage in women with placenta praevia: multicentre, double blind, randomised, placebo controlled, phase 3 trial | The BMJ
