Endometrial effects of levonorgestrel and estradiol: A Scanning electron microscopic study of the luminal epithelium

Abstract

Fertile women in the follicular phase possessed an uterine luminal surface with many ciliated cells and with non-ciliated cells, which carried numerous, fairly long microvilli. A moderate number of the non-ciliated cells had an irregular surface with small apical protrusions. Postmenopausal women had an endometrial surface containing rather flat cells. Ciliated cells were seldon encountered, and the non-ciliated cells possessed mostly only few short microvilli. When menopausal women had been wearing estradiol-containing intravaginal rings for three weeks, the uterine surface had developed many ciliated cells, and the non-ciliated cells now possessed many long microvilli. This appearance resembles that appearing during the follicular phase. Fertile women with levonorgestrel-containing subdermal implants or intravaginal rings showed a surface epithelium with few ciliated cells and with non-ciliated cells possessing short and irregular microvilli; that is, an epithelium less developed than that from a cyclic women. Adding estradiol to the levonorgestrel-containing intravaginal rings resulted in an estrogen response with an increase in number and length of the microvilli and an appearance of a few small apical protrusions.

PIP: This scanning electron microscopic study (SEM) investigated the extent of estrogenic influences on endometrium; biopsy specimens from 2 groups of women were compared, one group using a levonorgestrel-only containing vaginal ring and the other using a levonorgestrel-estradiol containing vaginal ring; these women were all fertile. To evaluate the effect of estradiol, biopsies were also taken from menopausal women using vaginal rings containing estradiol alone. These were all compared with control biopsies from normal fertile women from follicular phase-menopause. Fertile women in follicular phase possessed a uterine luminal surface with many ciliated cells and those nonciliated cells carried numerous, fairly long microvilli. Some nonciliated cells had irregular surfaces with small apical protrusions. Postmenopausal women's endometrial surfaces showed flat cells; ciliated cells were seldom seen, and nonciliated cells had mostly short, and very few, microvilli. Menopausal women, who had worn the estradiol ring for 3 weeks, showed ciliated uterine surfaces, and the remaining nonciliated cells now possessed long microvilli, similar to follicular-phase endometrium. Fertile women with levonorgestrel-only implants or rings showed surface epithelium with few ciliated cells and with nonciliated cells of short and irregular microvilli. Adding estradiol to the levenorgestrel ring gave an estrogen response with increased number and length of microvilli and the appearance of a few small apical protrusions.