We propose that TG and TEG will be more sensitive than traditional coagulation assays to detect physiologic variation in hemostasis, fibrinolysis, and platelet activation throughout the menstrual cycle. We expect that TG and TEG will better discriminate patients with vWD than traditional coagulation studies during the menstrual cycle. In this study we plan to measure TG and TEG in healthy women and women with von Willebrand's disorder during four phases of the menstrual cycle. We will compare specific measurements of endogenous thrombin generation potential from the TG and fibrinolysis and platelet activation from the TEG with standard measures of coagulation, fibrinolysis, and platelet activation markers during the menstrual cycle.