Cardiac function improves significantly after valve replacement, and pregnancy can occur 2 to 3 years after valve replacement in married women who wish to have children. Warfarin should be avoided in the first 3 months of pregnancy. Because warfarin can pass through the placenta, it can cause embryonic malformation and occasionally fatal hemorrhage if applied in the first 3 months of pregnancy. Since heparin does not cross the placenta, the drug can be used in pregnant women for anticoagulation. However, it has been reported that anticoagulation with heparin fails in many pregnant women after mechanical valve replacement and leads to serious maternal consequences. For this reason, many leading experts recommend that warfarin should be used in the fourth to ninth trimester of pregnancy in patients with mechanical valve replacement. It is also believed that the risk of maternal thromboembolism due to inadequate anticoagulation of heparin in the first 3 months of pregnancy is much greater than the teratogenic effect of warfarin. 1. Heparin is applied throughout pregnancy; 2. Warfarin is applied throughout pregnancy and switched to heparin at week 38 of gestation and cesarean delivery at week 40; 3. Heparin is applied during the first 3 months of pregnancy and switched to warfarin from month 4 until week 38 of gestation, then switched to heparin and cesarean delivery at week 40. Heparin was administered subcutaneously 2 times/d, starting with a full dose of 3500 U/d. Blood was checked at least twice weekly to monitor partial thromboplastin time (APTT). It should be noted that: Heparin requirements increase from the 7th month of pregnancy because of elevated heparin binding protein. Heparin should be discontinued 12 hours prior to cesarean delivery and restarted immediately after delivery and applied concurrently with warfarin for 4 to 5 days. Patients can usually be hospitalized 1 to 3 weeks before the expected date of delivery, during which anticoagulants are discontinued and heparin is used instead for anticoagulation. If preterm labor occurs, the mother and fetus are also safer. When cesarean delivery is used, the prothrombin time is checked first, and the patient is given vitamin K 120 mg intravenously after the onset of uterine contractions, and is rechecked after 4 hours; if the prothrombin time is close to normal levels, cesarean delivery is done immediately. Anticoagulation therapy was restarted 48 hours after surgery. Available evidence suggests that warfarin application in breastfeeding mothers does not produce anticoagulant effects in breastfed infants, so it is feasible to breastfeed the infant. If cardiac recovery is poor after valve replacement and hemodynamic improvement is slow, the pregnancy should be terminated. Anticoagulation for termination of pregnancy is discontinuation of anticoagulants for 2 to 3 days before surgery, monitoring of normal prothrombin time after surgery, and if necessary, intravenous vitamin K1. Anticoagulation is resumed 48 hours after surgery.