Gynecologic consequences of long-term, unopposed estrogen replacement therapy.

We evaluated the gynecologic risks of unopposed, long-term estrogen use in postmenopausal women. Our medical record review showed that unopposed estrogen users (mean dose, 0.9 mg of conjugated estrogens) had a significantly higher (P less than 0.001) incidence of abnormal vaginal bleeding, curettage, hysterectomy, and endometrial cancer. The ratios of occurrence of these events among users compared with non-users were 7.8, 4.9, 6.6 and 7.7. The prevalence of hysterectomy reached 28.2% of users compared with 5.3% of non-users, and endometrial carcinoma developed in 9.9% of users compared with 1.4% of non-users.