Morphology of menstrual hemostasis in essential menorrhagia

We performed a morphologic and morphometric study with light and electron microscopy on early menstrual hemostasis in five menorrhagic uteri and one control uterus, related the data to measured menstrual blood loss and compared the data with our previous study on normal menstruation. Menstrual blood loss ranged from 39 to 234 ml. Menorrhagic uteri contained large hemostatic plugs, protruding with a large part into the extravascular space. These plugs often consisted of loosely packed, poorly degranulated platelets with few fibrin fibers. Recanalized plugs, consisting of fibrin fibers and platelet remnants at the periphery of the vessel, were also observed in menorrhagic uteri. Using morphometry, we demonstrated a positive correlation between menstrual blood loss and the number of occlusive and nonocclusive hemostatic plugs, but not with other aspects of hemostatic plug formation such as the vessel area occluded by the plug, plug transformation, or intra- or extravascular localization of the plug. Vasodilation or endometrial height were not correlated with the amount of menstrual blood loss. These data suggest that essential menorrhagia is associated with fragile hemostatic plugs or with more extensive vessel damage.