Does menopause really cause sudden biological changes — a 'cliff'?

The evidence is contested. A Nature Medicine study suggests abrupt changes across multiple body systems starting about 15 years before the final period. Australian menopause specialists say 'cliff' is not a scientific term and the study design has important limitations. The broader message — that perimenopause involves real, progressive physiological changes — is well established.

Does this study mean I should start MHT sooner?

Not on its own. The finding that MHT was associated with smaller changes in the study is interesting but not conclusive — healthier women are more likely to use MHT, which complicates the interpretation. Any decision about MHT should be based on your symptom burden, medical history, and a conversation with your GP or women's health specialist.

The menopause 'cliff': what the contested new study actually shows

A study published this week in Nature Medicine has attracted headlines around the world with a striking claim: menopause does not bring gradual physiological change. Instead, according to researchers from Israel’s Weizmann Institute, it produces something they describe as a “cliff” — abrupt, step-like shifts visible simultaneously across bone health, liver and kidney function, blood chemistry, and blood fats.

The study is large. Researchers analysed over 300 million lab tests from more than 1 million women in the United States and Israel, collected between 1999 and 2024. The scale is genuinely impressive. So is the claim that these changes begin approximately 15 years before the final period — notably earlier than the 7-year estimate from the well-regarded SWAN longitudinal cohort.

The study also found that women on menopausal hormone therapy (MHT) showed smaller changes, particularly for bone, liver and kidney function.

Australian specialists are not convinced

The headline framing has met significant pushback from Australian menopause researchers, and it is worth unpacking why.

Martha Hickey from Women’s Hospital Victoria described “cliff” as “unnecessarily alarming” and noted it is not a scientific or medical term. She pointed to a methodological concern that is central to interpreting the MHT signal: the study is retrospective, and women who are healthier to begin with are substantially more likely to use MHT. That healthy-user bias means the apparent protective effect cannot be cleanly attributed to the treatment itself — it may largely reflect baseline health differences between MHT users and non-users.

Elina Safro from the Australasian Menopause Society called the “cliff” model implausible as a biological mechanism, while acknowledging that the 15-year early start is meaningfully different from previous estimates. Ada Cheung from the University of Melbourne offered the most measured take: the study supports the value of regular health checks around perimenopause, regardless of whether the “cliff” metaphor survives scrutiny.

Both-and: real changes, contested framing

The both-and framing here matters. The physiological changes of perimenopause are real, progressive, and — based on accumulated evidence including this study — begin earlier than many clinicians and patients expect. The SWAN longitudinal study found changes unfolding over approximately three years in the perimenopausal window; this new retrospective data puts the starting point 15 years earlier. Even if the “cliff” metaphor is incorrect, the implication that perimenopause is a decade-long biological transition rather than a two-year event deserves attention.

What remains genuinely contested: whether the changes are “abrupt” rather than gradual, whether the MHT signal is causal, and whether retrospective lab data from two non-Australian populations translates cleanly to clinical guidance for Australian women. Retrospective population data answers a different question from prospective trials — it can show that changes exist and correlate, but not that interventions based on those correlations will produce the outcomes the correlations suggest.

The study does not change the clinical evidence base for MHT in managing menopausal symptoms. That evidence base is separate, substantial, and supported by Australasian Menopause Society guidance for clinicians. What this study cannot do — and does not claim to do — is support initiating MHT in all perimenopausal women as a preventive strategy.

The Victorian context

This study arrives in a week when Victorian pharmacists became eligible to resupply MHT for the first time — dispensing a one-month supply for women aged 45–59 who have been on the same MHT formulation for at least six months and seen their GP in the past year. The change, announced on 8 October, extends the Chemist Care Now program to include MHT.

The access benefit is real. Estradiol patch shortages have been an ongoing problem, the TGA’s Serious Scarcity Substitution Instrument remains in effect until February 2027, and rural and regional women face the highest access barriers. RACGP Victoria’s Dr Aadhil Aziz has named the legitimate tension: a pharmacy resupply is not the same as planned clinical follow-up. Women experiencing changed symptoms, side effects, or who need a dose adjustment benefit from a GP who holds the full picture. The reform and the “cliff” study together underscore why the perimenopause consult — not just a pharmacy counter transaction — is worth protecting.

2 cents

What the “cliff” study offers that is clinically useful: a reminder that perimenopause is a long biological process, not a short event around the final period. Health monitoring in the decade before menopause — bone density, lipids, liver function, mood, blood pressure, cardiovascular risk — has a rationale that extends well beyond acute symptom management.

The “cliff” framing, taken literally, risks alarm without providing useful clinical direction. Menopause is not a sudden drop. It is a long corridor that many women have been walking for years before they had a name for what was changing.

Verdict: maybe — the underlying case for early perimenopause health monitoring is sound; the “cliff” claim is not ready to drive clinical practice changes.