Anticoagulation therapy in pregnant women with mechanical heart valve.

backgroundThis study aims to investigate the effects of various anticoagulant regimens on prosthetic valve-related complications and pregnancy outcomes including feto-maternal mortality and morbidity, and to identify the most optimal anticoagulation therapy regimen.

methodsAnticoagulant therapy regimens for pregnant women who underwent mechanical heart valve replacement between January 1990 and December 2015 was analyzed retrospectively. Seventy-two pregnancies among 57 patients after mechanical heart valve replacement were reviewed, and four different regimens were identified and evaluated during different trimesters of pregnancy.

resultsForty of 72 pregnancies resulted in healthy newborns; 35 (48.6%) healthy neonates, four (5.6%) premature births, and one (1.4%) low birth weight. Eighteen (25%) therapeutic and 12 (16.7%) spontaneous abortions, as well as two (2.8%) stillbirths occurred. Seven valve thromboses developed during pregnancy or the postpartum period. Bleeding occurred in six patients (10.5%) and peripheral embolism also occurred in six patients (10.5%). No maternal mortalities were recorded.

conclusionAlthough there is no consensus on the most optimal anticoagulant regimen during pregnancy, substituting warfarin with dose-adjusted unfractionated heparin or low-molecularweight heparin seems suitable to prevent teratogenicity and a high abortion rate in the first trimester. Low-molecular-weight heparin is practical to use and can be monitored reliably, resulting in successful pregnancy outcomes. However, warfarin throughout pregnancy ≤5 mg per day may be an alternative choice, if the risk of embryopathy is accepted by the pregnant woman.