The fibrinolytic enzyme system in normal menstruation and excessive uterine bleeding and the effect of tranexamic acid.

The fibrinolytic enzyme system of menstrual and peripheral blood was studied in three groups of women: Group 1, 20 subjects (mean age 37.2 years) with normal menstrual loss; Group 2, 20 patients (mean age 39 years) with dysfunctional uterine bleeding studied before treatment, and Group 3, during treatment with a fibrinolytic inhibitor, tranexamic acid (AMCA) (1 g 8-hourly). The fibrinolytic activity (plasminogen activator and plasmin) of menstrual blood was significantly higher than that of peripheral blood in the three groups (p less than 0.001). Both plasminogen activator and plasmin were higher in the menstrual blood of patients with menorrhagia (Group 2) compared with the control subjects (Group 1) (p less than 0.001 and p less than 0.1 respectively). Treatment with AMCA significantly reduced both plasminogen activator (p less than 0.01) and plasmin (p less than 0.05) in the menstrual blood of patients with menorrhagia (Group 3). No significant differences in fibrinolytic activity were found in peripheral blood between Groups 1 and 2; however, both plasminogen activator and plasmin were significantly lower (p less than 0.01) in Group 3 than in Group 2. Plasmin activity was also significantly lower (p less than 0.05) in Group 3 compared to Group 1. These findings confirm the presence of increased fibrinolytic activity in the uterus in excessive (dysfunctional) bleeding.