Pregnancy outcome after mechanical mitral valve replacement: a prospective study

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.

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 36(th) week.

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.

Fetal outcome was almost the same between the Warfarin and Heparin regimens. In maternal outcome, the Warfarin regimen is safer than Heparin.