PITUITARY-OVARIAN FUNCTION IN NORMAL WOMEN DURING THE MENOPAUSAL TRANSITION

Abstract

The excretion of follicle stimulating hormone (FSH), luteinizing hormone (LH), estrogens and pregnanediol was measured in weekly urine samples collected for 14-87 wk (median, 43 wk) from 31 perimenopausal women aged 36-55 yr (median, 50 yr). The results were compared with those found in 22 postmenopausal women aged 55.4 .+-. 5.4 yr (mean .+-. SD), and in 20 premenopausal women aged 44.4 .+-. 3.4 yr with regular, ovulatory, menstrual cycles. Women classed as perimenopausal had a recent history of irregular menstrual cycles following regular cyclicity. The hormone patterns observed in the perimenopausal women varied widely, both between individuals and from to time in the same individual. They ranged from ovulatory cycles with low premenopausal FSH levels, to transient episodes indistinguishable from those found in postmenopausal women with high FSH and LH levels. Between these extremes were patterns rarely seen at other times in reproductive life: in 14 women on 32 occasions lasting 2-9 wk, postmenopausal levels of FSH and LH occurred in association with high estrogen levels; in 18 women on 30 occasions lasting 208 wk, there was an elevation of LH (but not FSH) into the postmenopausal range; in 13 women on 26 occasions lasting 1-2 wk, there was an elevation of FSH (but not LH) into the postmenopausal range. These patterns were not seen in any of the premenopausal women. The approach of the menopause was marked by an increased incidence of high postmenopausal levels of FSH and LH. Ovulatory cycles were observed at all stages in the perimenopause, and occurred within 16 wk of the last menstrual period in 7 of the 13 women who became postmenopausal during the study. The appearance of high levels of FSH and LH is characteristic of the perimenopause and often precedes the sustained loss of sex hormone secretion by the aging ovary. Postmenopausal biochemical parameters are no guarantee of the postmenopausal state.