Human urinary follicle-stimulating hormone and human menopausal gonadotropin in induction of multiple follicle growth and ovulation.

Five normally menstruating women were treated, in an attempt to induce development of multiple follicles, with pharmacologic doses of purified human urinary follicle-stimulating hormone (hU-FSH) and (in another instance) with human menopausal gonadotropin (hMG) administered on the second and third days after the onset of menses. All of the cycles were ovulatory: the follicular phase was short and the luteal phase length was normal in both hMG and hU-FSH treatment. No substantial differences were seen between the two types of treatment in regard to plasma values of FSH, luteinizing hormone (LH), estradiol (E2), testosterone, and progesterone (P). FSH, E2, and P increased to supraphysiologic levels, and LH fluctuated within the normal range. On ultrasound examination, a large number of growing and matured follicles were visualized during both treatments: at human chorionic gonadotropin administration, multiple preovulatory follicles (greater than or equal to 15 mm) and only a few small follicles (less than 10 mm) were imaged, without any difference between the two types of treatment. Multiple corpora lutea were often obtained. These data underline that pharmacologic doses of FSH alone are able to induce the growth of multiple preovulatory follicles when the initiation of stimulation is timed early. Besides this, exogenous LH does not seem to interfere with follicular recruitment, and it is not required for follicular maturation and ovarian steroidogenesis when endogenous normal LH mean values are present.