You've probably heard that menopause arrives around 50. For many women, though, the body starts shifting long before that, in ways that are easy to miss. Years can pass before anyone connects the dots.
That gradual shift is called perimenopause. It can begin as early as the mid-30s, and it may run eight to 10 years before the final period, according to Cleveland Clinic. The average length is about four years, but it can stretch to eight.
A large international study published in January 2026 in Menopause, the journal of The Menopause Society, surveyed 17,494 women across 158 countries.
Led by Mayo Clinic and Flo Health, it found that fatigue, mood changes and sleep problems were far more common than the hot flashes many women expect.
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The eight signs that most often come first
The Menopause Society, the main US professional group on the topic, lists these common changes during the perimenopause years:
- Irregular periods, with cycles longer, shorter, heavier or skipped
- Sleep problems and night sweats
- Hot flashes
- Mood changes, including irritability and low mood
- Memory problems and brain fog
- Changes in sex drive
- Vaginal dryness and discomfort during sex
- Mild joint aches and pains
Irregular periods are the clearest hormonal signal. But they are often not the first thing a woman notices. Mood changes, poor sleep and brain fog can arrive years before cycles start to shift, which is why many women look for other explanations first.
Why the signs are so often missed
The Mayo Clinic and Flo Health study tells the same story. Among more than 12,000 women aged 35 or older, 83 percent reported fatigue and physical or mental exhaustion. Irritability and low mood were nearly as common.
Among the women who said they were actively in perimenopause, 95 percent reported exhaustion and 93 percent reported fatigue. Hot flashes, long seen as the signature sign, ranked further down.
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That gap matters. Stress, thyroid problems, anxiety and depression share many of the same symptoms. Many women spend years treating one complaint at a time without being told that perimenopause may be the thread tying them together.
Symptoms vary widely from woman to woman, and the mix changes over time. Perimenopause itself is a normal transition, not a disease.
When to talk to a doctor
Cleveland Clinic advises contacting a healthcare provider if symptoms are interfering with your quality of life. The same goes if menstrual bleeding is very heavy, contains large clots, or lasts longer than usual.
Spotting between periods or after sex, and periods arriving closer than 21 days apart, should also be checked.
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Any bleeding after menopause has ended needs attention too, since it is the leading warning sign of uterine cancer.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.