A Cochrane review included 12 studies with a total of 3 285 subjects at low risk of excessive bleeding undergoing elective caesarean section (n=2453) or spontaneous birth (n=832). Blood loss greater than 400 ml or 500 ml was less common in women who received tranexamic acid compared with placebo or no intervention (RR 0.52, 95% CI 0.42 to 0.63; 6 trials, n=1398) as well as loss more than 1000 ml (RR 0.40, 95% CI 0.23 to 0.71; 6 trials, n=2093). Tranexamic acid decreased the incidence of blood loss greater than 1000 mL in women with caesarean seciton (RR 0.43, 95% CI 0.23, 0.78; 4 trials, n=1534). Mean blood loss (from delivery until two hours postpartum) was lower in the group of women who received intravenous tranexamic acid postpartum (mean difference (MD) 77.79 mL, 95% CI -97.95, -57.64; 5 trials, n=1186). All women in both studies received routine uterotonics. Additional medical interventions and blood transfusions were less frequent in the tranwxamic acid group. No serious side effects were reported with tranexamic acid, though no data were available of thromboembolic episodes.
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment and blinding in half of the trials).