Low molecular weight heparin (LMWH) demonstrated the safety and efficacy in patients with valve prosthesis and successfully prevented or treated venous thromboembolic events in large series of pregnant women. Subcutaneous injection of LMWH at home was done for whole gestational period (39 weeks) in 29 year-old female patient with mechanical prosthetic valves in the aortic (St. Jude 21 mm) and mitral (St. Jude 29 mm) position. aPTT and echocardiography were regularly monitored once a month. Dosage of LMWH was used in a steady state. On delivery day, use of LMWH was stopped and full-term vaginal delivary of a healthy baby could be obtained without fetal loss, thromboembolic episodes. Warfarin was combined with LMWH for 3 days after delivery. One week later, left posterior tibial artery embolism developed.