This study aims to explore the causes of mechanical heart valve thrombosis during pregnancy, anticoagulation regimens, and the maternal and infant outcomes.

Based on the clinical data of 1 case treated at Peking University Shenzhen Hospital and 23 cases of pregnancy with mechanical heart valve reported in the literature, a retrospective analysis was conducted to review the anticoagulation treatment plans for preventing mechanical heart valve thrombosis during pregnancy and assess the maternal and infant outcomes.

The patient in this case, a 32-year-old woman, was admitted to the Department of Obstetrics and Gynecology of Peking University Shenzhen Hospital on June 27, 2023, due to "15^{+ 5} weeks of gestation and request for pregnancy termination". The patient underwent mitral valve replacement and tricuspid valvuloplasty due to rheumatic heart disease more than four years ago. After the operation, she has been on long-term oral warfarin anticoagulation, and changed to heparin anticoagulation during first trimester of pregnancy in another hospital. At 10 weeks of gestation, she developed chest distress, palpitation, and shortness of breath without obvious inducement, and the symptoms were obvious when she was physically active or supine. Imaging examination showed the formation of thrombosis and pannus in the mitral annulus, so the mechanical mitral valve replacement was performed again. After the operation, oral tocolysis drugs were used several times due to the "portent miscarriage". The patient and her family requested pregnancy termination at 15^{+ 5}weeks of gestation, and induced labor and curettage were performed at 16^{+ 4} weeks of gestation on July 3, 2023. A review of 23 pregnant patients with mechanical heart valve thrombosis reported in the literature from 2009 to 2023, combined with the information of this case, found that 23 patients had changed anticoagulant drugs, and 16 of them changed from warfarin to heparin in the first trimester. In addition, there were 1 case of unauthorized discontinuation of warfarin in early pregnancy, irregular use of warfarin, and replacement of anticoagulant drugs before pregnancy. There were 1 maternal death, 6 premature births, 6 miscarriages, and 1 warfarin infant.

Reasonable replacing anticoagulant drugs is the key to prevent valve thrombosis.