The histologic pattern of the endometrium was studied in 38 patients, 19 to 44 years old, with primary hypoestrogenic
amenorrhea treated by
estrogen replacement therapy. At the time of endometrial biopsy 3 patients were receiving
estrogens only and 35 patients were taking 1 of the following cyclic
estrogen-
progestogen combinations: 1)
conjugated estrogens, 1.25 or 2.5 mg per day, combined with
medroxyprogesterone, 5 or 10 mg for the last 5 to 10 days; 2)
ethinyl estradiol, 50 microgram per day, combined with
medroxyprogesterone, 5 mg per day for the last 5 days; or 3)
mestranol, 40 microgram per day, in combination with
norethindrone, 0.5 mg for the last 7 days. Evidence of
endometrial hyperplasia was found in 3 patients. Two of them were taking unopposed
estrogens and developed cystic
hyperplasia; the other patient, treated with
norethindrone in addition to
mestranol, disclosed focal cystic glandular
hyperplasia. This study and the review of the available data reported in the literature on the endometrial response to
estrogen therapy in patients with
gonadal dysgenesis stress the importance of appropriate
estrogen and
progestogen dosage to avoid the hazards of abnormal endometrial pattern in young patients receiving
estrogen replacement therapy.