[The endometrium under the effects of hormone replacement therapy in menopause with percutaneous estradiol and...

The aim of our study is to evaluate the effects of a new combined association of percutaneous estradiol with oral micronized progesterone during 25 days/month and to confirm that a low dose of progesterone (100 mg/day) can adequately counteract endometrial proliferation induced by estradiol.

78 endometrial tissue samples were obtained in a multicenter study on the effects of hormonal replacement therapy of the menopause. Endometrial biopsies were performed on average at the 6.6 month of the hormonal substitution (range: 5-13 months) after 12 days minimum exposure to progesterone. The morphological evaluation was performed blindly.

All endometria are only slightly developed, without hyperplasia. Four groups were individualized: subatrophic endometrium (3), quiescent endometrium (48), slightly active endometrium (18), and endometrium with marginal secretion (6). Rare mitosis images have only been found in slightly active endometria. Their number is always very much below the normal proliferative phase with only 3 cases between less than 3 and 6 mitoses per 1000 glandular epithelial cells.

A low micronized progesterone dose (100 mg/day) over a long period (25 days per month) allows to efficiently control the estrogen-induced endometrial proliferation. This adequate endometrial response is responsible for a high incidence of amenorrhea, often asked by patients, and for rare spottings.