RÉSUMÉ
Endometrial biopsies were taken from 40 women attending the Fertility Care Unit [FCU], Mansoura University Hospitals who were using Norplant for more than 6 months, thirty cases were complaining of menstrual disturbances and ten were regularly menstruating, Endometrial biopsies were also taken from 10 women attending the FCU and asking for IUCD insertion with no previous use of any hormonal therapy in the last six months and these cases were considered as control. Endometrial biopsies were subjected to light and electron microscopical examination to identify the ultrastructural changes of the endometrium among Norplant users aiming at better understanding of the mechanism of bleeding that occur in some Norplant users. Regressive to atrophic, suppressed and hyperplastic changes were observed in the endometrium of Norplant users complaining of irregular bleeding. It was found that Norplant induces alteration in the ultrastructure of endometrial cells, as gaping areas in the basement membrane, defective ciliogenesis, and irregularity of epithelium including necrosis and denudation. Moreover, endothelial hypertrophy of small blood vessels, and loss of the epithelium of the uterine lumen exposing blood vessels in the underlying stroma were also observed, especially among Norplant users with abnormal uterine bleeding. These endometrial ultrastructural changes may explain the mechanism of bleeding and hence can be a helpful guidance to the best therapeutic modality of abnormal bleeding in some Norplant users