About 14 years before the final period, FSH, a hormone that rises as the ovaries wind down, began rising faster, in a model built from routine blood tests of more than a million women in the US and Israel. Estradiol began falling faster about 12 years before. The same work found a sudden jump at the final period in 52 of 90 blood tests, not seen in men. The data are snapshots of different women, not the same women followed over time.
The other side The US SWAN study, which followed 1,215 women aged 42 to 52 at the start through their final period, found FSH began rising about 6 years before it and estradiol began falling about 2 years before. Randolph et al., J Clin Endocrinol Metab, 2011
October 2026 · Global · Checked by Yellow 19 October 2026
Who it covers
Cross-sectional laboratory data: US NHANES (1999 to 2022, about 36,000 women) and Israel's Clalit health insurer (1.3 million women aged 30 to 70, 2004 to 2024); over 300 million tests in all; menopause status self-reported; funded by the European Research Council and Weizmann Institute institutes; authors declare no competing interests
This card reports what research found. It is not medical advice.