Relationship Between the Concentrations of Estrogen and Progesterone Receptors and Endometrial Texture Estimated by Transvaginal Sonography in Pre-ovulatory phase

Kim, J H; Chae, H D; Hwang, W J; Kim, B H; Huh, J R; Kang, B M; Chang, Y S; Mok, J E

Abstract

It is thought that adequate development of the endometrium is important for implantation of fertilized embryos. Implantation is a highly complex process requiring continuous consequences of biochemical, physical interaction between the embryo and the uterus. There must be a communication between the epithelium and the stroma of the uterine endometrium. For the successful implantation, it is necessary that there is synchronization between the embryonic development and the endometrial changes. Hence, it has been suggested that the evaluation of uterine receptivity is important prediction of implantation. Transvaginal ultrasonographic estimation of thickness and texture of the endometrium has been widely accepted for evaluation of uterine receptivity despite of controversies. In recent days, it was reported that steroids receptors in the endometrium itself can be a possible factor for uterine receptivity. This study was performed to evaluate the relationship between ultrasonographic endometrial thickness and texture, and endometrial concentrations of steroids receptors-estrogen receptor[ER] and progesterne receptor[PR] in the pre-ovulatory phase of menstrual cycle. From Novemer 1995 to Octber 1996, forty-five infertile women with tubal factor infertility only were allocated to the study group. Transvaginal ultrasonographic measurement of endometrial thickness and texture was made on the day the leading follicle was up to 19 mm in pre-ovulatory phase of unstimulated, normal menstrual cycle. On the same day, endometrial biopsy was performed for immunohistochemical staining of ER and PR in the endometrium itself. When the patients were grouped into A group[centrally hyperechogenic triple line; n=17] and non-A group[n=28], there was no statistically significant difference in the endometrial thickness between the two groups[10.6+/-3.28 mm vs. 9.9+/-7.14 mm]. The proportion of the each steroid receptor that was stained strongly as grade III and IV by immunohistochemical staining of two groups were as follows; 1] ER of the epithelium [ER[epi]], 8/17[47.1%] vs. 13/28[46.4%], 2] ER of the stroma [ER[stro]], 5/17[29.4%] vs. 16/28[57.1%], 3]PR[epi], 5/17[29.4%] vs. 13/28[46.4%], and 4] PR[stro], 16/17[94.1%] vs. 19/28[67.9%], respectively. Although there was no statistical difference, there was tendency that PR[stro] of A group was higher than that of non-A group[p=0.06]. The patients were also grouped into three according to the endometrial thickness[< 6 mm group, 6~10 mm group, and > or = 10 mm group]. There were no differences among the three groups in the proportions of the each steroid receptor that was stained strongly as grade III and IV. In conclusion, it was not found that ER and PR have significant association with the endometrial thickness and texture in this study. However, the high PR of the endometrial stroma in the pre-ovulatory phase may be related to an adequate endometrial developmentl.