In normal pregnancy, the hemostatic balance is displaced toward hypercoagulability. The elevation in plasma levels of coagulation factors VII, VIII, and X and fibrinogen and the increased concentrations of plasminogen activator inhibitors [1,2] may predispose individuals to thromboembolism, especially near term [1,3]. Because human multifetal gestation requires still greater physiological alterations, the imbalance in hemostasis is further exaggerated. It has been suggested that the changes in the coagulation system near term may even mimic low-grade disseminated intravascular coagulopathy . However, for the majority of women with multifetal gestation, the coagulopathy observed in the laboratory is not clinically apparent . Despite the large body of research on the physiological adaptation to pregnancy, relatively little is known of the biological adaptation in general and the hemostatic changes in particular associated with multiple gestation. Copyright (C) 2000 Elsevier Science Ltd.