RESUMEN
30 normally menstruating women, 30 women wearing Lippes loops, 30 women wearing Cu T 200, 30 women wearing mumitiload and 20 women wearing progestasert were studied. The menstrual blood was collected on the first day of menstruation using plastic cups. The fibrinolytic activity of blood from different groups was assayed, using heated and unheated fibrin plates and measuring the area of lysis. A significant increase in the fibrinolytic activity was found in blood collected from wearers of Lippes loops, Cu T 200, and multiload when compared with normal women [P 0.001]. the highest increase was found in Lippes loops wearers, to a lesser extent in multiload wearers and the least increase in Cu T 200 wearers. No significant increase was found in progestasert users. The possible mechanism and the value of these findings are discussed