The Effect of Warfarin Dosage on Maternal and Fetal Outcomes in Pregnant Women with Prosthetic Heart Valves: A Comprehensive Review

Abstract

The management of anticoagulation in pregnant women with mechanical prosthetic heart valves (PHVs) poses a significant clinical challenge, requiring a balance between preventing life-threatening maternal thromboembolism and minimizing fetal harm. Warfarin, the most effective anticoagulant for valve protection, is teratogenic and associated with adverse fetal outcomes. This review synthesizes current evidence demonstrating that daily warfarin dosage is a critical factor stratifying these risks. High-dose warfarin (>5 mg/day) is associated with a substantially elevated risk of fetal warfarin embryopathy (up to 12.4%) and pregnancy loss. In contrast, low-dose warfarin (≤5 mg/day) carries a markedly lower risk of embryopathy (approximately 1.5%) and offers superior maternal thromboembolic protection compared to heparin-based regimens. Current guideline recommendations are therefore stratified by dose, favoring continued warfarin use throughout pregnancy for women maintained on ≤5 mg/day, while considering first-trimester heparin substitution for those requiring >5 mg/day. This review underscores the necessity for individualized, multidisciplinary management and informed shared decision-making, highlighting warfarin dosage as a pivotal element in optimizing outcomes for both mother and fetus.

Received Date: July 19, 2025                       

Accepted Date: August 11, 2025                       

Published Date: August 30, 2025

Available Online at: https://www.ijsrisjournal.com/index.php/ojsfiles/article/view/558