Endogenous luteinizing hormone release using human menopausal gonadotropins for in vitro fertilization.

This study demonstrates that luteinizing hormone (LH) release may occur despite sustained elevations of estradiol E2 in women receiving human menopausal gonadotropin. Mean levels of E2 did not correlate with the LH surge, however, the follicle number and a rapid rise in E2 did. Therefore, it appears that the protective influence of inhibitory proteins secreted by multiple follicles can be overridden, allowing spontaneous LH release.