Objective
To determine the effect of prophylactic tranexamic acid (TA) on calculated and measured blood loss after vaginal delivery in women at low risk of postpartum haemorrhage.

Methods
In this double‐blind randomised controlled trial, 120 women with a singleton pregnancy were randomly allocated to receive either one gram intravenous TA or placebo in addition to 10 IU oxytocin after delivery of the fetus. Calculated blood loss was determined based on haematocrit before delivery and 12–24 h postdelivery. The quantity of blood loss was measured during two time periods: from delivery of the fetus to placental expulsion and from placental expulsion to the end of the second hour after childbirth.

Results
The mean (SD) calculated total blood loss (519 (320) vs 659 (402) mL, P = 0.036) and measured blood loss from placental delivery to 2 h postpartum (69 (39) vs 108 (53) mL, P < 0.001) was significantly lower in the intervention group compared with the control group. There was no significant difference between groups in terms of blood loss from delivery of the fetus until placental expulsion. The frequency of calculated blood loss > 1000 mL was lower in the TA group (7% vs 18%, P = 0.048).

Conclusion
Prophylactic TA reduces blood loss after vaginal delivery in women with a low risk of postpartum haemorrhage. The prophylactic use of TA may reduce blood loss complications and enhance maternal health.