A huge new study suggests the body’s transition begins more than a decade before the last period, then shifts sharply around it. Most women are told that menopause is a gradual process, with changes starting a few years before the final period and slowly settling afterward. A major new study suggests the reality may look quite different: hormonal shifts that begin much earlier, followed by a sudden, body-wide change.
The research, published on October 12 in Nature Medicine by a team at Israel’s Weizmann Institute of Science, analyzed more than 300 million routine lab results from over one million women in the US and Israel.
What the Researchers Measured
The team, led by Uri Alon with first author Glen Pridham, used two large datasets: the US National Health and Nutrition Examination Survey, covering 1999 to 2022, and records from Clalit, Israel’s largest health organization, from 2004 to 2024. They borrowed a technique from astronomy, called deconvolution, to align each woman’s data to her own final menstrual period and reconstruct how 90 common lab tests change over the transition, according to Neo Science Hub.
A Step, Not a Slope
Of the 90 markers, 52 showed a significant jump around the final period. The changes affected sex hormones, bone markers, liver and kidney function, blood fats and blood chemistry. The authors describe it as a “physiological cliff.”
Associate Professor Mia Schaumberg of the University of the Sunshine Coast noted that the largest changes appeared in estrogen-sensitive systems such as bone and liver. The researchers also linked the transition to steeper increases in osteoporosis and cardiovascular outcomes afterward.
Hormones Start Shifting Much Earlier
The most surprising finding concerns timing. Anti-Müllerian hormone, a marker of ovarian reserve, began falling faster about 15 years before the final period. Follicle-stimulating hormone started rising faster about 14 years before, and estradiol began declining faster about 12 years before. Earlier estimates placed the start at around seven years before menopause.
“Our study extends the window for potential preventive care to almost a decade before menopause,” Alon said, according to Down To Earth.
Why Men Were Part of the Study
To check that the changes were linked to menopause and not simply to aging, the team compared women with men of similar ages. Men showed no comparable jumps.
Why Some Experts Urge Caution
Not everyone welcomes the framing. Professor Martha Hickey of the University of Melbourne called the “cliff” language “potentially alarming for women,” noting that the study does not show a dramatic physical or mental decline and that the evidence is low-level. Professor Andrew Shelling of the University of Auckland praised the unprecedented dataset but described the findings as “hypothesis-generating rather than conclusive.”
The authors themselves acknowledge limits: the data is retrospective, menopause status was self-reported, and lab changes do not necessarily mean illness.
What It Means for You After 45
The study does not change medical guidelines, but it is a good reason to have an informed conversation with your doctor in your mid-40s. Ask whether routine tests such as a lipid panel, liver and kidney function, and, when appropriate, a bone health assessment make sense for you, and discuss any symptoms early rather than waiting for your periods to stop.
Doctors have long said menopause changes start a few years before the last period. With 300 million lab tests pointing to a much earlier start, the conversation may begin sooner than many women expected.