Aim: Data from Japanese women have been lacking regarding hemorrhagic complications due to low-molecular-weight heparin (LMWH) as thromboprophylaxis. Thus, targeting Japanese women, we made an effort to determine: (i) whether the administration of LMWH soon after cesarean section increases the risk of hemorrhagic complications compared to that of unfractionated heparin; and (ii) how it elongates the activated partial thromboplastin time. Materials and Methods: We administered unfractionated heparin in the first half of the study period, and LMWH in the latter half. We examined: (i) the incidence rate of hemorrhagic complications; and (ii) preoperative and postoperative activated partial thromboplastin time, and we compared these in cases using unfractionated heparin and LMWH. Results: No clinically discernable thromboembolism occurred in either group. Hemorrhagic complications occurred in two of 140 women in the unfractionated heparin group and one of 131 women in the LMWH group. LMWH prolonged the activated partial thromboplastin time from 29.8 ± 2.6 to 34.8 ± 4.0 s. This prolongation was significantly shorter than that with unfractionated heparin (from 30.2 ± 2.6 to 36.5 ± 6.2 s). Conclusions: Compared with thromboprophylaxis with unfractionated heparin, thromboprophylaxis with early administration of LMWH after cesarean section did not increase the incidence of hemorrhagic complications and caused less prolongation of the activated partial thromboplastin time in Japanese women.
