Outcome of pregnancy in women with mechanical valves

In women who have prosthetic heart valves, pregnancy is risky for mother an d fetus. Heparin has been considered safer for the fetus than warfarin, but may not provide adequate anticoagulation for the mother. We examined prosp ectively gathered data from 100 pregnancies in 67 women with mechanical val ves (age range, 79 to 45 years). A subgroup of 20 patients was compared wit h a control group of relatives and neighbors who conceived at similar ages. Fetal loss occurred in 44 of the 100 pregnancies, due to the following cau ses: spontaneous abortion (28), intrauterine fetal death (4), stillbirth (3 ), neonatal death (1), premature birth (2), Rh incompatibility (2), and mat ernal death (4). Age parity, atrial fibrillation, and left ventricular enla rgement did not affect the outcome. Tricuspid valve disease that required d iuretics was associated with a higher rate of fetal loss (17 out of 23 preg nancies, versus 27 out of 77; p = 0.001), but did not affect the mother. Of 66 pregnancies in which the mother was on heparin, 38 (57.6%) resulted in a healthy baby, compared with 18 out of 34 (52.9%) pregnancies in which the mother was on warfarin (p = NS). All thromboembolic complications occurred with heparin therapy (9 cases; p = 0.02). In the control group, fetal loss was 24%, due exclusively to spontaneous abortion. Women with mechanical valves have higher rates of fetal loss and maternal c omplications. In our study, tricuspid valve disease adversely affected feta l outcome, which is a new finding that warrants further study. Warfarin was more effective than heparin in preventing thromboembolism in the mothers, and it did not show a significant impact on the babies.