Objective: To assess the efficacy of tranexamic acid in reduction of blood loss and pervention of postpartum hemorrhage after vaginal delivary. Methods: This is a multicentric prospective randomized double blind placebo controlled trial. 200 pregnant women were randomized to receive either 60 mg/kg of tranexamic acid (TA) (n=100) or placebo (n=100) intravenously in the second stage of labour. Postpartum blood loss was collected and measured accurately from placental delivery to 2 hours postpartum and adverse effects of were observed. Results: The mean estimated postpartum blood loss was significantly lower in women treated with tranexamic acid compared to women in the placebo group    ( 442.50 ± 128.55 versus 555.75 ± 191.88, respectively; p < 0.001), and the proportion of women in the tranexamic acid group who had an estimated blood loss  ≥ 500 mL was significantly lower than in the placebo group( 3 [3 %] versus 9 [9%],relative risk [RR]=0.30; 97% confidence interval [CI] 0.11 to 0.78;P<0.05). Maternal and neonatal outcomes did not differ significantly between both groups. Conclusion: The addition of tranexamic acid to the active management of third stage of labor after normal vaginal delivery is effective as a prophylaxis against post-partum hemorrhage. It can significantly reduce blood loss during and after delivery.