Abstract: Mechanical valvular replacement surgeries represent highly operated cardiac surgeries globally. In patients who receive replacement surgeries, postoperative anticoagulation therapy for pregnant women requires special attention. Administration of warfarin, the most common anticoagulant after surgery, increases fetal damage. Instead of decreasing fetal damage, heparins used as replacement drugs dramatically increase the rate of embolism. Of the new drugs, dabigatran is confirmed to exert a poor effect in preventing thrombus from mechanical heart valves. Rivaroxaban and apixaban have achieved no better results in thrombogenesis. No clinical or experimental findings have been reported about the side effects of these new drugs to fetuses. This paper will review the research progress of the prescribed drugs in thrombus prevention.