What happens in the female body at different stages of life, and how do age-related changes affect health? Researchers at the Weizmann Institute set out to answer these questions. On October 12, 2026, a study by a team from the Weizmann Institute was published. The researchers analyzed more than 300 million laboratory test results from women in the United States and Israel. The work was led by Glen Pridham and Yoav Hayut from Uri Alon’s lab. Of the 90 measures studied, 52 changed in a step-like pattern around the final menstrual period, affecting hormones, bone metabolism, lipids, and other body systems.
Menopause is the permanent cessation of menstruation. It is diagnosed retrospectively after 12 months without a period, provided there is no other reason for its absence. The new study describes average patterns of change, but it does not predict the date of menopause for any specific woman and does not, on its own, call for additional tests.
October 18 is World Menopause Day. These findings offer a reason to talk about the transition beyond the familiar list of hot flashes and night sweats.
The number is impressive, but it refers to results—not 300 million tests. The authors used data from the US NHANES health examination program for 1999–2022 and records from the Israeli healthcare organization Clalit for 2004–2024. The latter included 1.3 million women aged 30–70.
Imagine a graph showing measurements for every 50-year-old woman. One woman may still have regular periods, while another’s periods stopped several years ago. Averaging by age mixes different stages of the transition and smooths out the changes.
The authors used a mathematical deconvolution method to reduce this blurring and reconstruct average patterns relative to the final menstrual period. They did not find comparable step-like changes in hormone levels among men of a similar age.
The main analysis was retrospective and cross-sectional: the researchers did not follow each participant throughout the entire transition. The Clalit database did not include menstrual history, so the accuracy of the reconstruction depends on the assumed distribution of age at the final menstrual period. A large dataset can reveal patterns, but it cannot replace long-term follow-up of the same women.
The most pronounced systemic shifts in the study involved several groups of measures:
Bone metabolism. Markers related to bone turnover changed. These markers alone cannot diagnose osteoporosis.
Lipid metabolism. Blood lipid levels changed, and clinicians assess them alongside other cardiovascular risk factors.
Liver markers. Their average patterns also shifted. This does not mean that every woman develops liver disease.
Osmolality. This measure reflects the concentration of dissolved particles in body fluids.
At the same time, some changes appeared favorable. Iron, hemoglobin, and red blood cell levels shifted in a direction associated with less anemia. The authors link this to the end of regular menstrual blood loss.
So the image of a “physiological cliff”—an impression that can easily arise when reading the news—is misleading. Independent expert Martha Hickey called this metaphor unnecessarily alarming in an interview with ABC and emphasized that it is not a medical term. A step in an average graph does not mean that every woman’s health suddenly worsens.
The most unexpected part of the study is its reconstruction of early hormonal changes. According to the authors’ model, these changes began to accelerate long before the final menstrual period. However, these findings are based on separate NHANES subsamples, not the full dataset of 300 million test results.
Hormone | Change in average pattern | Number of participants |
|---|---|---|
Anti-Müllerian hormone, AMH | Decline began to accelerate around 15 years beforehand | 2406 |
Follicle-stimulating hormone, FSH | Increase began to accelerate 14 ± 1 years beforehand | 3035 |
Estradiol | Decline began to accelerate 12 ± 1 years beforehand | 4621 |
These hormones reflect different aspects of ovarian function. AMH is associated with the ovarian follicle reserve; FSH helps stimulate follicle growth; estradiol is produced mainly by developing follicles. As ovarian function changes, the relationships between these signals change too.
However, detecting an early shift in an average curve does not mean identifying the start of clinical perimenopause for every woman. Perimenopause is a transitional period during which menstrual cycles and well-being may change. The model described in the study cannot tell you how long it will last based on a single test.
An average hormone curve describes a group of women. It cannot tell you how many years you have left before menopause.
There is no need to order a large hormone panel because of this news. UK professional guidelines published in Clinical Endocrinology in 2022 recommend diagnosing perimenopause and menopause in women aged 45 and older who have typical symptoms without confirmatory hormone tests, when the diagnosis is clear.
This does not mean that symptoms should go uninvestigated. Changes in your cycle, weakness, or palpitations can have other causes. Focus on what you have actually noticed. Consider making a doctor’s appointment if at least one of these applies to you:
I started bleeding again after 12 months without a period.
My bleeding has become noticeably heavier or lasts longer than usual.
I am under 45, and my periods have become infrequent or stopped.
Hot flashes or night sweats regularly wake me up and make it hard to function during the day.
Palpitations, weakness, or unexplained weight changes persist regardless of hot flashes.
I had a fracture after a minor injury or a fall from standing height.
This list is not a diagnosis. Bleeding after menopause has been established needs to be checked; heavy bleeding accompanied by weakness, dizziness, or fainting requires urgent medical care.
The practical takeaway is an opportunity to discuss health with your doctor beyond hot flashes: blood pressure, lipids, bone health, sleep, and bleeding. Which tests you need will depend on your age, symptoms, medical history, and family history.
In an El País article, Uri Alon suggested considering an initial bone density scan at an earlier age. This is his personal proposal, not a new recommendation established by the study. This research does not mean that everyone needs bone density screening earlier than usual.
Among women who used menopausal hormone therapy, laboratory shifts were weaker on average. But an observational association does not prove a protective effect: the groups may have differed in their baseline health and access to care. Causal conclusions require randomized trials. We discuss the indications and limitations of treatment separately in our article on hormone therapy for menopause.
Even if your test results are within the normal range, disrupted sleep or pain during sex deserve their own conversation. A lab report cannot measure how difficult everyday life feels for you.
You cannot determine menopause based on the absence of bleeding while using hormonal contraception. The medication can change bleeding patterns and hormone levels. A doctor can help you choose an appropriate way to assess it; you do not need to stop contraception on your own just to get tested.
Yes. Pregnancy is possible as long as ovulation continues, even if your periods are irregular. Menopausal hormone therapy is not a substitute for contraception. Talk to your doctor about how long to continue using contraception.
No. Having your uterus removed while your ovaries remain does not, by itself, mean you are in menopause. You will no longer have periods, but your ovaries may continue to function. Your doctor will take the extent of the surgery and your symptoms into account and may order tests if needed.
Not necessarily. Family history can offer a rough guide, but it cannot provide an exact prediction. Neither your mother’s age at menopause nor a new population-level model can tell you your personal date.
You can start with a gynecologist or primary care doctor. Tell them about all the changes you have noticed, including sleep, your menstrual cycle, and medications. This will help determine whether you need to see another specialist.
No. Someone else’s treatment plan may not be right for you. The choice of medication depends in part on whether you have a uterus, your bleeding pattern, and any medical contraindications. Before starting treatment, discuss the indications and limitations of hormone therapy with your doctor.
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