RESUMEN
PIP: This study dealt with the possible local tissue reaction induced by IUDs and its possible antifertility role. Premenstrual endometrial biopsies were taken from 50 women using the copper IUD for periods ranging from 5 months to 3 years, together with a control group of 10 nonusers. The immunohistochemical localization of the total immunoglobulins and the immunoglobulin G (IgG) concentrations in the endometrial tissue revealed a significant increase in copper IUD users when compared with the controls. Histochemically, there was a decrease in alkaline phosphatase activity, RNA, DNA, and the acid mucopolysaccharide reactions in the endometrial biopsies from women with copper IUDs. These changes were more apparent in specimens taken less than 1 year after copper IUD insertion, especially in the surface epithelium. The reaction showed progressive increase in the 2nd and 3rd year after copper IUD insertion. It can be claimed that, early after insertion, copper ions, when released in reasonable amounts, lead to metabolic changes in the endometrium, rendering it unfavorable for implantation. It is very likely that, through time, the oxidative changes occurring on the copper wire surface interfered with the release of ions, thus predisposing it to gradually act as an inert foreign body.^ieng