Secretory changes in preovulatory endometrium during controlled ovarian hyperstimulation with buserelin acetate and human gonadotropins

Twenty-one patients with unexplained infertility underwent controlled ovarian hyperstimulation with buserelin acetate and human menopausal and chorionic gonadotropins, and follicular growth was monitored by ultrasonography and daily 17β-estradiol (E ₂) assays. Endometrial biopsy was performed when E ₂ levels were ≥250 pg/mL per follicle and the follicular diameter was ≥17 mm. As controls, we studied 20 preovulatory endometrial biopsies from patients with a male infertility factor. The biopsy material was examined at light, scanning, and transmission electron microscopes, and a morphometric analysis was performed. Preovulatory endometrial mucosa during controlled ovarian hyperstimulation showed accentuated proliferative aspects in both the glandular and stromal components and more frequent early secretory phenomena compared with the controls. The preovulatory progesterone (P) levels observed in our study seem to exclude the possibility that such early secretory aspects of the hyperstimulated endometrium are because of higher P concentrations in patients compared with controls.