Endometrium and plasma hormone profile in the peri-menopause and post-menopause.
Endometrial histology and plasma levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17 beta-oestradiol (E2), oestrone (E1) and progesterone (P) were studied in 483 women over a period of 13 yr (6 yr before and 7 yr after the start of definitive amenorrhoea, defined as the last menstrual bleeding). The patterns for these parameters were established on the basis of the results of 1227 gonadotrophin and steroid determinations and 721 endometrial biopsies. Three periods were identified. During the first, from year-6 to year-3, gonadotrophin levels increased gradually, while those of E2 remained normal, with peaks in some cases. Mean plasma P levels were within the normal range until year-3, but they then decreased progressively. Endometrial histology was similar to that observed during reproductive life. In the second period, from year-3 to year+1, there was a concomitant rise in gonadotrophins as the E2 and P levels decreased. However, at the start of definitive amenorrhoea, the mean E2 and P levels fluctuated between 60 and 100 pg/ml and between 2 and 3 ng/ml, respectively. The endometrium reflected this decrease in E2 and P production. It was not atrophic but proliferative when definitive amenorrhoea commenced. During the last period, from year+1 to year+7, gonadotrophins reached a plateau at high levels, while those of E2 continued to fall, reaching very low values at year+4, after which they reached a plateau. P levels were at the detection limit of the technique. The correlations between all plasma steroid levels and endometrial histology demonstrated discrepancies in 30% of cases: proliferative or hyperplastic endometria were seen at E2 levels of under 60 mg/ml, atrophic endometric at E2 levels of over 60 pg/ml and secretory endometria at very low P levels.