RESPONSE TO CLOMIPHENE CITRATE CHALLENGE TEST IN NORMAL WOMEN THROUGHPERIMENOPAUSE

Objective: To identify the physiological changes that discriminate sub groups of women along the reproductive continuum. Methods: This prospe ctive study was carried out at the outpatient facility of George Washi ngton University Medical Center and the outpatient clinic of the Natio nal Institutes of Health Clinical Center, Twenty-five female subjects were divided into 4 biologically distinct groups: group 1 (n = 4) regu lar menstrual cycles and under age 35; group 2 (n = 11) regular cycles and over age 35; group 3 (n = 6) irregular cycles and over age 35, an d group 4 (n = 4) menopausal. Measurements of basal and stimulated gon adotropins (immunoactive LH, LH-I; bioactive LH, LH-B; immunoactive FS H, FSH-I) and E-2 were obtained before and after administration of clo miphene citrate, Basal and stimulated gonadotropins and E-2 were analy zed to discriminate between subject groups 1-4, The relationship of me nstrual cyclicity to hormone levels was evaluated. Results: Basal leve ls of LH-I, LH-B, FSH-I could discriminate only group 4 vs. groups 1-3 . Stimulated levels of FSH-I and E-2 were significantly different for group 2 vs, 3 and group 2 vs. 4, Group 1 was similar to group 2. Both stimulated FSH-I and stimulated LH-I and LH-B differentiated group 4 v s. groups 1-3. The LH-B:LH-I (B:I) ratio was not discriminatory after the clomiphene citrate challenge test (CCCT). Conclusions: Baseline ho rmone values were useful in distinguishing only group 4, CCCT unmasked differences in FSH and E-2 between irregularly and regularly cycling older women; these differences were not seen with LH-B or B:I ratio, S timulated FSH was the most useful hormone parameter and paralleled men strual cycle regularity as a useful discriminator in older women.