Determinants of early follicular phase gonadotrophin and estradiol concentrations in women of late reproductive age.

BACKGROUND: FSH and estradiol measured during the menstrual (basal) phase of cycles predict the success of infertility treatment; but the role of these hormones as markers for ovarian reserve in normal populations needs further study. METHODS AND RESULTS: From a cohort study of depressed and non-depressed women, a subset of 406 non-depressed women between the ages of 36 and 45 years with spontaneous periods were selected and their concentrations and determinants of basal hormones measured at study entry, 6 and 12 months later were described. FSH and LH increased significantly over the 12 months of observation (P