ENDOMETRIAL MORPHOLOGY DURING HORMONE REPLACEMENT THERAPY WITH ESTRADIOL GEL COMBINED TO LEVONORGESTREL-RELEASING INTRAUTERINE-DEVICE OR NATURAL PROGESTERONE

Objectives. To evaluate endometrial responses to three different forms of amenorrhea-inducing HRT in postmenopausal women. Material and meth ods. Fifty-one postmenopausal women completing a one-year HRT trial wi th percutaneous estradiol gel containing 1.5 mg estradiol daily combin ed with a levonorgestrel-releasing intrauterine device (LNG-IUD) (n=18 ), or natural progesterone 100 mg daily orally (n=19) or vaginally (n= 15) during 1-25 calendar days of each month. Endometrial thickness and uterine size were measured by transvaginal ultrasound, and endometria l cytology/histology was assessed from specimens taken by needle aspir ation before the study and at 12 months. Results. Before medication, t he median endometrial thickness was 2.0 mm in the LNG-IUD group, 2.4 m m in the oral P group and 2.5 mm in the vaginal P group. At 12 months of therapy the respective values, 3.0, 2.7 and 2.4 mm, did not differ significantly from the initial values. LNG-IUD induced epithelial atro phy in all women, which was accompanied by stromal decidualization in 12 women. On the contrary, only four women in the oral P group and fiv e women in the vaginal P group had an inactive or atrophic endometrium . The remaining cases were dominated by proliferative features. No hyp erplasia was seen in any of the groups. Conclusion. LNG-IUD appeared t o be an effective method of counteracting the stimulatory effect of es trogen on the endometrium, whereas natural progesterone given orally o r vaginally was not sufficiently effective in this function at the dos es used. The vaginal and oral administrations of progesterone did not differ from each other in this respect.