Pregnancy with St. Jude Medical Mitral Valve Prosthesis

From 1986 to 1995, 513 young women of childbearing age (11 to 45 years) underwent mitral valve replacement with a bileaflet St. Jude Medical prosthesis. Twenty-one patients became pregnant within 3 years postoperatively. The mean age of these patients at the onset of pregnancy was 27 ± 8 years (range, 16 to 43 years). Follow-up was complete for all pregnant patients. Of 11 who continued to take warfarin during pregnancy, one had a premature delivery, 2 had spontaneous abortions, and 8 had therapeutic abortions. Five patients who ceased oral anticoagulant therapy had normal deliveries but 4 underwent reoperation for valve thrombosis postnatally, with concurrent left hemiplegia in one case. The other 5 patients adhered to an anticoagulation protocol for pregnancy; there were 3 normal deliveries, 1 premature birth, and 1 abortion. There is a high risk of thromboembolism in patients with mechanical heart valves whose anticoagulants are interrupted during pregnancy. We believe that careful supervision can reduce maternal morbidity and mortality.