Characteristics of endometrial receptivity in women with different endometrial thickness

Abstract

Aim: to evaluate the expression of estrogen (ER) and progesterone (PR) receptors in the endometrium during the "implantation window" in women with a history of reproductive dysfunction with different endometrial thickness.Materials and Methods. A prospective single-center cohort comparative study was conducted. The main group included patients with hypoplastic (< 7 mm according to ultrasound data on preovulatory days) endometrium (n = 52), the comparison group consisted of women with normal endometrial thickness (n = 62) (women of both groups with reproductive dysfunctions of unclear cause), the control group included 16 healthy fertile women. An aspiration biopsy of the endometrium was performed on day 6–8 after ovulation with simultaneous collection of peripheral blood sample to measure level of estradiol (P). Endometrial biopsies were examined with histological and immunohistochemical (expression of ER, PR) methods.Results. All women had an ovulatory cycle, serum progesterone level ≥ 16.1 nmol/L (6–8 days after ovulation) and normoestrogenemia. E2/P was similar in all cohorts (p > 0.05). Indicators of endometrial expression of ER, PR, similar to healthy women (n = 16), were found in 21 % (n = 11 out of 52) and 32 % (n = 20 out of 62) in women from main and comparison groups, respectively. The remaining 79 % (n = 41 out of 52) of women with "thin" endometrium (main group) and 68 % (n = 42 out of 62) of patients with normal endometrial thickness (comparison group) had ER and PR expression indices in the endometrial glands and stroma with significant differences (p < 0.05) in all parameters (excepting PR in the endometrial stroma) from those of healthy women (control group), but without relevant differences between these cohorts (p > 0.05) regardless of endometrial thickness.Conclusion. In women with a history of reproductive disorders, parameters of ER and PR expression similar to those in women without reproductive problems, were noted with a "thin" (< 7 mm) endometrium by 50 % less often than those with normal thickness of the uterine mucosa. At the same time, the "thin" endometrium is not an absolute predictor of disorders of the hormone-receptor characteristics of the endometrium: in every fifth case, magnitude of endometrial expression ER, PR similar to healthy women were determined.