This study was conducted on 66 pregnant women with prosthetic heart valves on anticoagulant therapy and 132 pregnant normotensive, non-diabetic women without heart problems taken as a control group. Our cases were followed up through out pregnancy in high risk obstetric unit Kasr El-Aini hospital, Cairo University in the period from the first of September 2008 to December 2009 to investigate the outcome of pregnancy as regard fetal and maternal morbidity and mortality.We found that 9.01% of our cases had hemorrhagic complications, 6.06% had thrombo-embolic complications and fetal losses were about 15.1%; of these losses 9.1% were due to spontaneous abortion, 3% neonatal death and 3% intra-uterine fetal deaths.In our study, we found that the incidence of neonatal deaths was more in pregnant women taking warfarin at a dose more than 5 mg. We also found no relationship exists between INR value and fetal losses. In our study, the position of the prosthetic valve had no impact on the outcome of pregnancy. We found also that cesarean section was the safest mode of delivery as it is a scheduled procedure and patients were well prepared before it.