The Haemostatic Mechanism and Menstruation: The Role of Intra-Uterine Contraceptive Devices

An ultrastructural study of menstrual blood in normal menstruation and dysfunctional uterine bleeding

Menstrual fluid was obtained from the uterine cavity and vagina in 20 women within the first 48 h of menstruation. Ten of the women had normal menstrual cycles and blood loss and ten were patients with dysfunctional uterine bleeding. The menstrual samples were examined by electron microscopy for the presence of fibrin and platelets and nearly all were found to contain both fibrin and aggregating platelets. By a simple quantitative system no differences in fibrin and platelet content were found between samples collected from the uterine cavity or the vagina. Likewise no difference was found in the morphology of fibrin and platelets between women with normal menstrual loss and patients with dysfunctional uterine bleeding.

Changes in thrombin-stimulated platelet malondialdehyde production during the menstrual cycle

Forty normal women had thrombin-stimulated platelet malondialdehyde (MDA) production measured during their menstrual cycle. Twenty women in this group were taking the combined oral contraceptive pill (OCP). Platelet MDA production was found to fall by 30% during normal menstruation and the week when the subjects were not taking a combined OCP, but it remained constant throughout the remainder of the cycle. No significant change in initial platelet aggregation response to stimulation by thrombin, change in plasma thrombin clotting time, plasma heparin neutralising activity (HNA), or plasma antithrombin III (AT-III) activity was seen when the platelet MDA production was reduced. The bleeding time results showed some variation throughout the menstrual cycle but these did not appear to be related to the variation in platelet MDA production.