Scientists have reported drastic changes in the body during menopause

Menopause can be accompanied by dramatic changes in several body systems at once, from bone tissue to liver and kidney function. This conclusion was reached by researchers who analyzed more than 300 million results of surveys of women in the United States and Israel. At the same time, changes in individual hormonal parameters were detected more than 10 years before the last menstruation. The results obtained allow us to take a fresh look at the transition, which is usually associated primarily with the cessation of menstruation and hot flashes. What exactly scientists have discovered, why the first hormonal shifts can appear long before menopause, and what questions remain open — in the material of Izvestia.

Menopause affects more than the reproductive system

According to the World Health Organization, natural menopause occurs in most women between the ages of 45 and 55. It is established after 12 consecutive months without menstruation, unless it is related to other physiological or pathological causes. The previous transition period may last several years.

Its manifestations vary. Some women experience almost no discomfort, while others experience hot flashes, night sweats, sleep disorders, anxiety, and mood swings. Vaginal dryness and soreness during sexual intercourse are possible. But menopause is also associated with less noticeable changes: decreased bone density, changes in body composition, and cardiovascular risk.

The new work is devoted specifically to the physiological side of this transition. Scientists were interested in how the objective indicators of the body change relative to the last menstruation. This approach allows us to study processes that are not necessarily accompanied by pronounced symptoms.

Menopause is based on the depletion of the ovarian follicle reserve, followed by a change in the level of sex hormones. However, the consequences of this restructuring go beyond the reproductive function. Estrogen sensitivity helps explain why different tissues and systems react at the same time.

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Why did researchers need 300 million survey results?

Uri Alon's team used arrays of medical data from the United States and Israel, covering the period from 1999 to 2024. Collectively, they included more than 300 million survey results from more than a million women.

The main difficulty was choosing the starting point. If we compare the indicators only by age, the changes are smoothed out: the women of the same age may have had their last menstruation in different years. Therefore, the team reconstructed the average trajectories relative to this event. The principle is similar to the elimination of blurring in an astronomical image: mathematical processing helps to restore details that are hidden during normal averaging.

It wasn't like every participant had been monitored for decades. The method reconstructs the overall picture from large amounts of data and does not determine the date of future menopause for a particular woman.

The results of the two samples showed a similar trend of changes. This reinforces the conclusion that the discovered pattern is not limited to a single studied population. However, the scale of the data does not negate the limitations of the method itself.

What scientists have called a "physiological cliff"

In the American sample, statistically significant drastic changes were found in 52 of the 90 indicators studied. They concerned sex hormones, the state of bone tissue, liver and kidney parameters, the biochemical composition of blood and lipids — fats and fat-like substances.

On the restored charts, the transition resembled a step: around the last menstruation, the indicators changed more sharply than one would expect with a smooth age shift. The authors called this feature a "physiological cliff."

The researchers did not find a similar pattern in a comparable analysis of male data. This supports the assumption that the identified transition is related to menopause and is not explained solely by increasing age.

According to her assessment, in many systems there was a marked jump in indicators that went beyond the age dynamics in the male comparison group.

However, a sharp change in the average indicator does not mean that every woman develops a disease at one point. A statistical pattern describes a group. Individual manifestations of the transition may vary significantly, and changes in laboratory values require a separate clinical assessment.

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Why were the bones and liver particularly sensitive?

The most pronounced shifts were observed in systems closely related to the action of estrogens. Schaumberg drew attention primarily to the bone tissue and liver. The indicators of the systems whose connection with estrogens is weaker did not show the same noticeable changes.

This pattern helps to understand why menopause can affect different aspects of health at the same time. The cessation of menstruation is the most obvious sign of transition, but hormonal changes also affect processes that a woman cannot directly feel.

However, changes did not always mean deterioration. In the original source, the authors identified indicators of iron, hemoglobin, and red blood cells: their shifts corresponded to a decrease in the risk of anemia. A possible explanation is the cessation of regular blood loss during menstruation.

Therefore, the word "cliff" should not be understood as a universal description of destructive processes. The study shows different responses of different indicators to the same physiological transition.

Hormonal changes were detected 12-15 years before the last menstruation

Another result concerns the time when hormonal levels begin to change. According to the reconstruction, an accelerated decrease in the anti-Muller hormone was observed approximately 15 years before the last menstruation. The growth of follicle—stimulating hormone accelerated in about 14 years, and the decrease in estradiol in 12 years.

These results extend the time span in which biological changes associated with future menopause may be noticeable. Hormonal shifts were detected long before the cessation of menstruation and could precede more drastic changes in other indicators.

Schaumberg believes that the revealed sequence gives grounds to explore the possibility of earlier forecasting of systemic changes. However, there remains a significant distance between detecting a pattern and creating a reliable personal forecast.

It cannot be concluded from the work that in all women menopause "begins 15 years" before the last menstruation. It deals with individual hormonal trajectories, rather than the onset of symptoms or an established diagnosis. Moreover, the result of one analysis does not allow us to count the exact number of years before the cycle ends.

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What the study is changing for women

The work provides additional reasons to consider menopause as a systemic physiological transition. The assessment of this period should not be limited to the question of hot flashes: sleep, well-being and bone condition are also important.

However, the study is retrospective, and information about menopause is partly based on the responses of the participants themselves. Therefore, the accuracy of the reconstructed time pattern and its applicability to an individual require further verification.

Practical support measures are already described in the medical guidelines. The NHS advises maintaining regular physical activity, including bone-building exercises and strength training, following a balanced diet with calcium sources, and maintaining a sleep pattern. Quitting smoking is also included in the recommendations.

For symptoms that interfere with daily life, WHO recommends discussing available care options with a medical professional. Menopause itself is not a disease, but the problems associated with it do not necessarily need to be tolerated without support.

The new analysis clarifies the possible sequence of this transition: early hormonal shifts, followed by more dramatic changes in a number of indicators around the last menstruation. The next question for researchers is whether these data can help identify women at increased risk in advance and choose measures that will improve their health, not just laboratory values.