Background: Anticoagulant therapy can be required during pregnancy with prosthetic heart valves. Warfarin and heparin provide real protection against thromboembolic phenomena, but they also carry serious risks for the fetus and the mother. In an attempt to identify the best treatment for pregnant women with cardiac valve prostheses who are receiving anticoagulant, we studied 19 pregnancies, the warfarin was discontinued and heparin was administered every 12 hours by subcutaneous injection in doses adjusted to keep the midinterval aPTT in the therapeutic range(at least 2-2.5 control) from the conception to the 12th week of gestation and oral antiocagulant was then administered until the middle of the third trimester in the therapeutic range(at least 2 INR), and heparin therapy was restared until delivery. Also in order to avoid an anticoagulant effect during delivery, it has been our practice to instruct women to either discontinue their heparin injections with the onset of labur or to stop heparin injections 12 hours prior to the elective induction of labour. Result: The outcome of 19 pregnancies managed with above protocol was spontaneous abortion in 3 cases, voluntary termination in 2 cases, premature delivery at 35 weeks in 1 case and delivery at full-term in 14 cases. There was no maternal morbidity and moratality and fetopathy. Conclusion: We conclude that in the second and third trimester of pregnancy, warfarin provide effective protection against thromboembolism, Oral antiocagulant therapy should be avoided in 2 weeks before delivery because of the risk of serious perinatal bleeding caused by the trauma of delivery to the anticoagulated fetus. However, the substitution of heparin at first trimester and 2 weeks before delivery reduce the incidence of complications.