PIP: IUD-induced bleeding may occur in the form of 1) an increase in the menstrual blood loss at cyclical periods, 2) increased duration of bleeding at periods, and 3) intermenstrual bleeding and spotting (1-4). The type of device used, surface area, duration of usage, the variable individual response to the same type of IUD, the cultural and social background of the woman, previous menstrual pattern and amount of blood previously lost, different thresholds of discomfort in different women, and parity may exert influences on the frequency of bleeding, acceptance, and indication and motivation for the IUD removal due to bleeding. With the exception of the progestasert IUDs, all devices increase (MBL) menstrual blood loss by 50-100% over preinsertion levels. Compared to inert devices, copper IUDs are associated with less MBL. Few studies have been done to analyze the pattern of (IMB) intermenstrual bleeding in IUD users. The frequency of IMB is about 40% in the 1st cycle for women using copper devices but the amount of blood lost in these cases is minimal. The incidence of IMB with copper devices is higher than with inert IUDs. 30% of all IUD users are expected to experience a prolonged menstrual cycle. It appears that in spite of the reduction of MBL with progestasert IUDs, they are associated with a prolongation of menstrual periods, more so than the copper and the inert devices. The pathogenesis of bleeding disturbances in IUD users is multifactorial and different etiologies have been suggested for different types of bleeding disturbances. Local increase in fibrinolytic activity is the most accepted cause for the increase of menstrual blood loss. All IUDs, with the exception of the progestasert, increase fibrinolytic activity of the endometrium. Various factors come into play in the pathogenesis of IUD-induced bleeding. The distortion of the endometrial vasculature by the presence of IUD can be explained by 1) the direct effect of the device on the superficial vessels causing abrasions and erosions with possible irregular bleeding and/or 2) the pressure distortion of the IUD, probably transmitted through endometrial tissue and resulting in endothelian injuries with defect formation in the small superficial vessels of the functional zone of the endometrium. The injury of vessel will lead to interstitial hemorrhage with the release of blood in an irregular pattern to the uterine cavity. The defective hemostatic mechanism in the IUD-exposed endometrium also contributes to the bleeding.