Hormonal and Metabolic Factors Influence the Action of Progesterone on the Endometrium of Women with Polycystic Ovary Syndrome

Hormonal and metabolic factors may influence endometrial quality and interfere with the action of progesterone. Therefore, the aim of our study was to address this issue. Participants were recruited from an outpatient reproductive endocrinology clinic at an academic tertiary medical care centre. All subjects underwent endometrial biopsy (EB) in the follicular phase of the cycle prior to treatment. Thereafter, they were treated with micronized progesterone (400 mg/day × 10 days intravaginally) from days 14–28 of the next cycle. A second EB was performed between days 21–24 of the cycle (the second phase). The metabolic and hormonal serum levels were evaluated during the implantation window. EB samples were analysed using light microscopy for histomorphometric analysis. The endometrium of women with Polycystic Ovarian Syndrome (PCOS) in the second phase demonstrated a uniform surface epithelium with less leukocyte infiltration and an absence of apoptotic figures compared to the control group. (p < 0.021). The thickness of the surface epithelium in the second phase of the PCOS group correlated positively with free and bioavailable testosterone values. The number of stromal cells increases with increasing insulin levels. Our results suggest that histomorphometric abnormalities of the endometrium persist and are linked to androgen and insulin levels despite progesterone supplementation in PCOS.