Anticoagulation in pregnancy with mechanical heart valves: 10-year experience.

Anticoagulation in pregnancy was evaluated in 33 women with a mechanical heart valve prosthesis who had 53 pregnancies between 1994 and 2006. Their mean age at valve operation was 24.4 +/- 5.4 years, and 22 (67%) had isolated mitral valve disease. Of these patients, 22 had a single pregnancy, 5 had 2 pregnancies, 3 had 3, and 3 had 4. In 43 pregnancies, the patients took warfarin throughout; in the other 10, heparin was used in the first trimester followed by warfarin until the last 15 days. Mean international normalized ratio and warfarin levels before, during, and after pregnancy were similar. Complications occurred in 3 (6%) women who had thrombosed valves: 2 (20%) in the heparin group and 1 (2%) who had warfarin only. Live births resulted from 37 (70%) pregnancies. There were significantly more abortions in the heparin group (6; 60%) than the warfarin group (8; 19%). Hemorrhage requiring transfusion occurred in 2 (5%) patients in the warfarin group. All live births resulted in healthy babies. It was concluded that anticoagulation with warfarin is safe during pregnancy in women with mechanical heart valves.