Follicle-stimulating hormone and oestradiol levels during perimenopause in a cohort of Japanese women.

CONTEXT

There had been a lack of longitudinal studies regarding follicle-stimulating hormone (FSH) and oestradiol (E2) during perimenopause for non-Caucasian populations.

OBJECTIVE

To investigate FSH and E2 levels during perimenopause in a Japanese cohort.

DESIGN AND SETTING

The Adult Health Study is a longitudinal population-based study. Perimenopausal women from this study cohort were followed between 1993 and 2003.

PARTICIPANTS AND MAIN OUTCOME MEASURES

Non-menopausal women, aged 47-54 years, were measured in terms of FSH and E2 levels every 6 months. For 89 women whose FSH and E2 levels were measured within 3 months from their final menstrual period (FMP), trends of FSH and E2 within 21 months of FMP were investigated at 6-month intervals.

RESULTS

Follicle-stimulating hormone and E2 levels within 3 months from FMP showed wide ranges. Neither FSH nor E2 levels differed by age, weight or duration of amenorrhoea. Although FSH increased and E2 decreased during perimenopause, FSH and E2 levels at a single time point were found to not be a reliable marker of biological menopause, as hormone levels in and between the subjects showed wide variation and any trend in one individual was not necessarily one directional.

CONCLUSIONS

Among Japanese women who had natural menopause around the age of 50, hormone levels in and between individuals showed wide variation throughout perimenopause with a converged biochemical menopausal pattern characterised by high FSH and low E2 at about 2 years after FMP.