Tranexamic acid reduces postpartum haemorrhage in placenta praevia caesarean delivery

OBJECTIVE: To investigate whether prophylactic tranexamic acid reduces the incidence of postpartum haemorrhage in women with placenta praevia compared with placebo. DESIGN: Randomised, double blind, placebo controlled, phase 3 study. SETTING: 24 maternity units across China between July 2023 and March 2025. PARTICIPANTS: 1732 women with placenta praevia undergoing caesarean delivery. INTERVENTIONS: Participants were randomly (1:1) assigned to receive prophylactic oxytocin and either tranexamic acid (1 g in 10 mL) or placebo (10 mL normal saline) diluted in 40 mL normal saline intravenously over 10 minutes, initiated within five minutes of umbilical cord clamping. MAIN OUTCOME MEASURES: The primary outcome was postpartum haemorrhage, defined as calculated estimated blood loss ≥1000 mL or as red cell transfusion within two days after delivery. Serious adverse events included thromboembolic events, seizures, acute kidney or liver injury, and maternal death. RESULTS: Of 1732 women with placenta praevia who were randomised, 38 were excluded because they withdrew consent or were determined to be ineligible after randomisation. Primary outcome data were available for 99.8% (1691/1694) of the remaining women. Placenta accreta spectrum was diagnosed in 303 participants (17.9%). The primary outcome occurred in 29.7% (251/845) of the tranexamic acid group and 35.1% (297/846) of the placebo group (relative risk 0.85, 95.2% confidence interval (CI) 0.75 to 0.96; P=0.01). The rates of serious adverse events were similar between the tranexamic acid group and placebo group (0.5% (4 of 837) 0.5% (4 of 845); relative risk 1.01, 95% CI 0.25 to 4.00). CONCLUSIONS: In women with placenta praevia who underwent caesarean delivery and received prophylactic oxytocin, treatment with tranexamic acid resulted in a statistically significant yet modest reduction in the incidence of postpartum haemorrhage, with no signal of increased serious adverse events. TRIAL REGISTRATION: ClinicalTrials.gov NCT05811676.