Daily blood hormone levels related to the luteinizing hormone surge in anovulatory cycles.

We have evaluated daily blood levels of gonadal steroids and trophic hormones in the cycles of four ovulatory and six anovulatory patients with a luteinizing hormone (LH) surge. The cycles of anovulatory nonhirsute patients were characterized by a premature and blunted LH surge and by low levels of follicle-stimulating hormone (FSH) throughout the study period in the face of normal tonic and peak levels of estrone and estradiol (E2). These observations, together with decreased levels of prolactin, suggest a hypothalamic pituitary abnormality as the cause of anovulation in these patients. The cycles of anovulatory hirsute patients were marked by a decrease in E2 production and a blunted and delayed E2 peak. Androgen levels were elevated throughout the cycle and may have a direct inhibitory effect on ovarian folliculogenesis. The LH/FSH ratio in the follicular phase was high in both groups of anovulatory patients when compared with ovulatory controls; however, the shifts in gonadotropin levels producing the increase in this ratio were different for these two groups.