Faculty of Health Sciences School of Patholgy 8601804k erine.gregersen@nhls.ac.za / The oral anticoagulant, warfarin, when administered in pregnancy, can cause warfarin embryopathy, fetal central nervous system abnormalities, spontaneous abortion and fetal intrauterine death. Women with prosthetic heart valves usually require warfarin in pregnancy because of their high risk for thromboembolic complications. Anticoagulation regimens in pregnancy in these women aim to balance the fetal effects of warfarin with maternal risks of thromboembolism. This study was conducted by structured interview of 124 black urban South African women of childbearing age, who had at least one warfarin-exposed pregnancy. The study aimed to determine the pregnancy outcomes in this cohort, their awareness of the effects of warfarin in pregnancy, and what management practices, as reported by them, had occurred with regard to their anticoagulation in pregnancy and what genetic counselling they had received. There was a significant difference in outcome between warfarin-exposed and non-exposed pregnancies; 55.2% (123/223) of warfarin-exposed pregnancies ended in the birth of an abnormal baby, spontaneous abortion or intrauterine death. The warfarin embryopathy rate was estimated at 4.5 – 5.4%. Most women reported having been given information about warfarin in pregnancy, though their awareness about the personal and fetal effects of warfarin was often inaccurate. Of warfarin-exposed pregnancies, 95% were reportedly exposed during critical weeks six to ten of pregnancy, and >50% after 36 weeks. Only 5/124 (4%) interviewees had genetic counselling. Poor pregnancy outcomes, lack of awareness about the effects of warfarin in pregnancy, and management practices at odds with international regimens are all areas highlighted by this study that require urgent attention in this high-risk group of women.