Effects of estriol administration on human postmenopausal endometrium.

Forty eight women with atrophic endometrium were treated with estriol, 1 mg twice daily, by mouth for a minimum of 10 days and a maximum of 25 days. Vaginal hysterectomy was then performed and specimens were examined histologically. Results showed that estriol produces endometrial hyperplasia in 70.8% of the examined women; only 29.2% of the patients retained atrophic endometrium after treatment.