Eur Heart J

Mechanical valves, use of LMWH associated with worse outcomes among pregnant women

April 22, 2025

Study details: The ESC EORP Registry of Pregnancy and Cardiac Disease III prospectively enrolled 613 pregnancies in women with prosthetic heart valves from January 2018 to April 2023. The study evaluated the relationship between anticoagulation practices and pregnancy outcomes in women with mechanical (n=411) and biological (n=202) heart valves.

Results: Women with biological valves had a higher chance of an uncomplicated pregnancy and live birth compared with those with mechanical valves (79% vs. 54%; P < .001). Thromboembolic and hemorrhagic complications were more common with low-molecular weight heparin (LMWH)-based regimens. Valve thrombosis occurred in 6% of women, with a higher risk associated with mitral prosthetic valves (odds ratio 3.3; 95% confidence interval, 1.9-8.0). Anti-Xa monitoring didn’t significantly reduce thromboembolic events (P = .060).

Clinical impact: The findings highlight the advantages of biological valves over mechanical valves in pregnant women, suggesting a need for careful anticoagulation management. LMWH regimens require close monitoring to mitigate thromboembolic risks, especially in women with mechanical mitral valves.

Source:

van der Zande JA, et al; ROPAC investigators. (2025, April 16). Eur Heart J. Pregnancy with a prosthetic heart valve, thrombosis, and bleeding: the ESC EORP Registry of Pregnancy and Cardiac disease III. https://pubmed.ncbi.nlm.nih.gov/40237423/