Relationship between endometrial estrogen and progesterone receptors, and sonographic endometrial appearance in the preovulatory phase

Objectives: The purpose of the present study is to evaluate the relationship between endometrial concentrations of estrogen receptor (ER) and progesterone receptor (PR), and sonographic endometrial findings in the preovulatory phase of menstrual cycle. Study Design: In 45 cycles of 45 infertile women with tubal factor only, transvaginal sonographic assessments and biopsy for immunohistochemical staining of the endometrium were made in the preovulatory phase of unstimulated, normal menstrual cycle. Immunohistochemical localization of ER and PR was scored according to intensity of staining and proportion of cells specifically stained in glandular epithelium and stroma, and the results were analyzed according to the sonographic endometrial thickness (10 mm) and pattern. Endometrial patterns were classified as A, centrally hyperechogenic triple‐line pattem or non‐A, not triple‐line. Results: There were no significant differences in the endometrial thickness, serum estradiol level and serum progesterone level between A and non‐A groups. The receptor scores of epithelial and stromal ER and epithelial PR were comparable in A and non‐A groups. However, the receptor score of stromal PR was significantly higher in A group, with 4.8 ± 1.4 compared with 2.7 ± 1.7 in non‐A group ( P < 0.001). There were no differences in the receptor scores of epithelial ER, epithelial PR, stromal ER and stromal PR among the 3 groups according to the endometrial thickness. Conclusions: This study suggests that high PR expression in endometrial stroma could be related to the sonographic triple‐line or multilayered pattern of endometrium in the preovulatory period.