MORPHOLOGY OF HAEMOSTASIS IN MENSTRUAL ENDOMETRIUM

Abstract
Light microscopy, EM and immunofluorescence were used to study the endometrium from 9 human uteri removed during the first 72 h of normal menstruation. During premenstrual spotting, stromal disintegration and vessel lesions without any hemostatic reaction were seen. Up to 20 h after the onset of menstrual bleeding, blood extravasation was prominent in the functional endometrium. The vessels in this layer were partly or totally sealed by intravascular thrombi functioning as hemostatic plugs. The thrombi contained various amounts of platelets and fibrin and were shed with the tissue. New plugs formed up-stream in the same vessels. Twenty hours after the onset of menstruation, most of the functional endometrium had been desquamated. From 20-72 h after the start of menstrual bleeding, no thrombi or a few were seen. Hemostasis may then be caused by adherence of vessel lips.