The effect of follicle-stimulating hormone without additional luteinizing hormone on follicular stimulation and oocyte development in normal ovulatory women

Twelve normally menstruating women were stimulated with (1) human menopausal gonadotropins (hMG) containing follicle-stimulating hormone (FSH) and luteinizing hormone (LH) and (2) FSH only to induce growth of multiple follicles for oocyte retrieval. Maturation of the follicles and presumptively the oocytes was assessed by daily serum estradiol (E₂) values, the response of the vaginal epithelium, and cervical mucus. The growth and number of follicles were measured by ultrasound daily. Human chorionic gonadotropin was administered as a surrogate LH surge. The hMG cycles were compared with the FSH-only cycles in relation to serum E₂ and oocyte maturation, fertilization, transfer, and pregnancy rates. Five of eight cycles adequately stimulated with FSH only resulted in successful pregnancies. FSH without additional LH can initiate and maintain E₂ function and allow oocyte maturation to proceed up to the terminal maturation, which is associated with the LH surge. The effect of LH may be to hasten follicular atresia in the developing cohort of follicles.