Prostaglandins and menorrhagia.

This paper reviews the various theories offered to explain excessive menstrual blood losses whether these are of primary origin or induced by IUD. An increased concentration of prostaglandins in endometrial tissue at the onset of menstruation may contribute to heavy menstrual bleeding. The mechanism of action is not clear, but prostaglandins may affect the stability of lysosomes which in turn lead to increased release of various proteinases. These in turn may disturb the hemostatic mechanism of the endometrium. Prostaglandins may also affect platelet aggregation and/or various coagulation factors and cause vasodilation - all mechanisms may theoretically alter the hemostasis of the endometrium. Treatment of menorrhagia with a prostaglandin synthetase inhibitor, naproxen, resulted in a significant reduction in menstrual blood loss in women with primary menorrhagia as well as with IUD-induced excessive menstrual blood loss. The reduction amounted to about 30%, which is lower than the reduction obtained by treatment with antifibrinolytic agents or oral contraceptives.