Background and aim of the study: Currently, there is no clear consensus on the optimal type of cardiac valve prosthesis that should be placed in women of childbearing age. The risks of reoperative surgery for bioprosthetic valves must be weighed against those of anticoagulation therapy required for mechanical valves. Bioprosthetic valves placed in women of childbearing age are not necessarily superior to mechanical valves in terms of maternal or fetal outcomes.
Methods: A retrospective analysis was performed of early and late outcome in 103 women of childbearing age (mean age 28.3 +/- 5.1 years; range: 18-35 years) who underwent mechanical (n = 63) or biological (n = 40) valve replacement between January 1982 and July 2002.
Results: Eleven of the 40 women (28%) with biological valves had 19 pregnancies (13 vaginal births; three caesarean sections). Twelve of the 63 women (19%) with mechanical valves had 37 pregnancies (nine vaginal births, four caesarean sections). All of the women with mechanical valves became pregnant while receiving warfarin, and were subsequently placed on heparin or enoxaparin. No bleeding complications or birth defects were observed in either group. The incidence of miscarriages (32% (12/37) versus 11% (2/19), p = 0.09) and therapeutic abortions (32.4% (12/37) versus 5.3% (1/19), p = 0.06) were greater in the group with mechanical valves than with bioprosthetic valves. Freedom from reoperation at five and 10 years for biological versus mechanical valves was 79% versus 90%, and 38% versus 82%, respectively (p < 0.01), with no reoperative mortality.
Conclusion: Biological valves are recommended in women of childbearing age, despite the fact that no birth defects were seen in children born to women with mechanical valves on warfarin, because the teratogenic effects of warfarin may be masked by the high rate of miscarriages and therapeutic abortions in this group.