Postpartum hemorrhage (PPH) is one of the leading causes of maternal mortality, posing a more prominent threat especially in developing countries. How to effectively prevent and manage postpartum hemorrhage has long been a key focus of clinical obstetric practice. As a synthetic lysine analog and antifibrinolytic agent, tranexamic acid (TXA) plays an increasingly important role in the treatment of postpartum hemorrhage. This article provides a detailed analysis of the application of tranexamic acid in postpartum hemorrhage.
Mechanism of Action of Tranexamic Acid
Tranexamic acid is a synthetic lysine analog classified as an antifibrinolytic agent. Its mechanism of action involves competitively binding to the lysine-binding sites on plasminogen molecules, thereby inhibiting the activation of plasminogen and blocking the fibrinolytic process. At high doses, it can also directly inhibit plasmin activity, further reducing the degradation of fibrin clots.
In simple terms, when postpartum hemorrhage occurs, both the coagulation system and the fibrinolytic system are activated simultaneously. The coagulation system attempts to form blood clots to stop bleeding, while the fibrinolytic system works to dissolve these clots. If the fibrinolytic system becomes overactive, bleeding can become difficult to control. Tranexamic acid helps the coagulation system achieve effective hemostasis by suppressing excessive fibrinolytic activity.
Indications
Tranexamic acid is primarily indicated for: All patients diagnosed with postpartum hemorrhage, regardless of the cause (e.g., uterine atony, placental factors, or soft tissue lacerations of the birth canal). It yields particularly favorable therapeutic effects when bleeding is accompanied by a tendency toward hyperfibrinolysis.
Recommendations for TXA Use in Postpartum Hemorrhage in Authoritative Guidelines Worldwide
World Health Organization (WHO)
The WHO updated its guidelines for the management of postpartum hemorrhage in 2017, recommending the use of tranexamic acid for postpartum hemorrhage: In addition to conventional treatment, intravenous tranexamic acid should be administered as early as possible when postpartum hemorrhage occurs. Specific dosage and administration: Initial dose of 1g via intravenous infusion (slow bolus after dilution, duration not less than 10 minutes); a repeat dose of 1g may be given 30 minutes later if bleeding is not controlled. The guidelines emphasize that tranexamic acid should be used within 3 hours after childbirth to maximize the reduction in bleeding-related mortality risk.
This recommendation is based on the results of the large-scale randomized controlled trial (RCT) – WOMAN (World Maternal Antifibrinolytic Trial). The study demonstrated that early administration of tranexamic acid after childbirth significantly reduces the risk of maternal death due to hemorrhage by approximately 20%-30% without increasing the incidence of serious adverse reactions.
Other International Authorities
In addition to the WHO, other prestigious organizations have also recommended tranexamic acid for the treatment of postpartum hemorrhage in their respective guidelines, including the Royal College of Obstetricians and Gynaecologists (RCOG, 2016), the American College of Obstetricians and Gynecologists (ACOG, 2017), and the International Federation of Gynecology and Obstetrics (FIGO, 2022).
Chinese Guidelines
The Obstetrics Group of the Society of Obstetrics and Gynecology of the Chinese Medical Association issued the Guidelines for the Prevention and Management of Postpartum Hemorrhage (2023), which explicitly recommends the use of tranexamic acid:
Tranexamic acid should be administered as early as possible once postpartum hemorrhage occurs to reduce blood loss. Administration within 3 hours after childbirth is emphasized. Specific dosage and administration: Intravenous route; initial dose of 1g via intravenous drip (slow infusion after dilution, duration not less than 10 minutes); if bleeding persists, a repeat dose of 1g may be given 30 minutes later.
In the early stage of severe postpartum hemorrhage, significant enhancement of fibrinolytic activity and depletion of fibrinogen are common, making antifibrinolytic agents effective. Aligned with international guidelines, Chinese guidelines list tranexamic acid as a key therapeutic drug for postpartum hemorrhage, emphasizing early and adequate administration.
Correct Usage of Tranexamic Acid
Route of Administration
Tranexamic acid is mainly administered intravenously for the treatment of postpartum hemorrhage. Specific methods:
Dosage
Timing of Administration
The timing of tranexamic acid administration is critical. Ideally, the first dose should be administered within 3 hours after childbirth. Studies have shown that administration within 3 hours yields the most significant reduction in mortality; while use beyond 3 hours still provides some benefit, the magnitude of mortality reduction is significantly diminished.
Post-Administration Monitoring
During medication, closely monitor the mother’s vital signs, blood loss volume, and changes in coagulation function. For patients with persistent bleeding, determine whether to continue administration or adjust the dosage based on clinical conditions.
Contraindications
❖ Patients with a tendency or high risk of thrombosis (e.g., history of deep vein thrombosis, pulmonary embolism).❖ Patients with ongoing or recent arterial or venous thrombotic events (e.g., myocardial infarction, cerebral infarction, pulmonary embolism).❖ Patients allergic to tranexamic acid or other amino acid hemostatic agents.❖ Patients with confirmed disseminated intravascular coagulation (DIC).
Precautions
Controversies Regarding Prophylactic Use
It is noteworthy that the role of tranexamic acid in the prevention of postpartum hemorrhage remains controversial. Current evidence suggests that prophylactic use of tranexamic acid may not provide additional benefits for puerperae who have not experienced postpartum hemorrhage. Most guidelines do not recommend routine prophylactic use for all puerperae unless definite high-risk factors exist. The WHO’s 2025 Consolidated Guidelines for the Prevention, Diagnosis and Treatment of Postpartum Hemorrhage explicitly states that tranexamic acid should only be administered after the onset of postpartum hemorrhage and is not recommended as routine prophylaxis during vaginal delivery or cesarean section.
References
Author Information
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