Objective: Pregnancy in a woman with thrombosis of heart valve prosthesis at the 25th week of gestation and fetal death during reimplantation of prosthesis with the use of extracorporeal circulation. Subject: Case report. Setting: Department of Gynecology and Obstetrics, 2nd Medical Faculty of Charles University, Motol Hospital, Prague. Subject and Method: Patient L. Š., 24 years old, first pregnancy, admitted to coronary heart unit at the 25th week of gestation with a blocked heart valve prosthesis, NYHA IV, left heart failure, and pulmonary edema. There was an insufficient anticoagulation therapy during pregnancy and a thrombosis of the prosthetic heart valve was suspected from that reason. Reimplantation of a prosthetic heart valve with the use of extracorporeal circulation was indicated in spite of a possible risk for the fetus. The thrombosis was confirmed during cardio surgical operation and a change of the prosthesis was successfully performed. After the patient was converted to extracorporeal circulation, bradycardia and intrauterine fetal death occurred. With regard to the patient’s coagulation and circulatory instability, further management was necessary because of fetal death – termination of pregnancy by minor caesarean section was the only alternative. Six hours later an 850 g weight dead fetus was delivered. There were no serious complications during the postoperative period. Conclusion: Reimplantation of a prosthetic heart valve from vital indication was performed at the 25th week of gestation. After conversion of mother to extracorporeal circulation, fetal death occurred. The patients was released with satisfactory cardiopulmonal compensation.

        Key words: pregnancy, prosthetic heart valve, thrombosis, reimplantation, extracorporeal circulation