Pregnancy Outcome after Mechanical Mitral Valve Replacement: A Prospective Study

Background: Pregnant patients with mechanical heart valves require anticoagulation. The risk of bleeding and embryopathy associated with oral anticoagulants must be weighed against the risk of valve thrombosis. Methods: In this prospective study, undertaken between 1999 and 2009, 53 pregnancies (47 women with mechanical mitral valves; 29.8 ± 4.8 years old) were studied. Patients were divided into two groups: group I (n = 43) received Warfarin throughout the pregnancy, while group II (n = 10) received Heparin in the first trimester and then Warfarin until the 36th week. Results: Thirty-two (60.4%) pregnancies resulted in live births, whereas 18 (34%) abortions, 2 (3.8%) stillbirths, and one (1.9%) maternal death occurred. In group I, there were 26 (60.5%) live births, one (2.3%) stillbirth, and 15 (34.9%) abortions. In group II, there were 6 (60%) live births, one (10%) stillbirth, and 3 (30%) abortions. There were no significant differences between the two groups in terms of fetal outcome. Thirty-nine (90.7%) of the pregnancies in group I and 50% of those in group II (p value = 0.001) were without complications. There were no congenital malformations in the two groups. Conclusion: Fetal outcome was almost the same between the Warfarin and Heparin regimens. In maternal outcome, the Warfarin regimen is safer than Heparin.