Endometrial morphology in women exposed to uterine systems releasing progesterone.

A blind study was done in 402 endometrial biopsies of women who had intrauterine devices releasing different daily amounts of progesterone or a placebo (empty device): 175 were obtained in what presumably was the proliferative phase and 227 in the secretory stage, as all these subjects were normal, healthy women with a history of previous fertility. With all dose levels of the progesterone-releasing devices there was variation of the endometrium general pattern and the over-all picture varied from normal secretory to suppressed endometrium. In addition to these changes of the endometrial pattern, in 231 specimens there was significant inflammatory infiltration and in six cases even plasma cells were seen. Predecidual reaction was frequently seen and in 45 cases it was diffuse and marked. The significance of these data is discussed on the grounds of the frequent similarities of the changes here reported with those in women using combined oral steroids for contraception.