Perimenopause and Long-Term Health: The Midlife Transition That Matters

You are between 38 and 45. You sleep badly although you are not especially stressed. Your mood swings in a way it never used to, and your periods no longer arrive on time. At your annual check-up the doctor says “everything is normal”. You are not “too young”, and you are not imagining it. What you may be feeling is perimenopause, and the link between perimenopause and long-term health is one a routine check-up does not capture. See what a “normal” health check does and doesn’t tell you.

What is perimenopause?

• Perimenopause: the transition before menopause, when oestrogen and progesterone fluctuate unevenly.
• Menopause: the point at which periods have stopped for 12 consecutive months.
• Typical timing: mid-40s to mid-50s, sometimes earlier.

Perimenopause is the transition before menopause, when oestrogen and progesterone levels swing unevenly before the ovaries gradually stop functioning. Menopause itself is the point at which periods have stopped for 12 consecutive months. According to the US National Institute on Aging, most women enter the transition in their mid-40s to mid-50s, though some notice changes earlier. One hospital-based study in southern Thailand found an average age at menopause of 48.7 years (PubMed), so the transition can start in the late 30s to early 40s.

It is a whole-body matter. Oestrogen receptors are found throughout the body, so the effects reach beyond the menstrual cycle to bone, heart, brain, muscle and skin at the same time.

How does perimenopause affect long-term health?

This is why timing matters. The bone figures above describe changes that happen before the final period.

Which signs should you raise with a doctor?

These are prompts for a conversation, not a way to diagnose yourself:

• Cycles that become irregular, shorter or longer than before.
• Sleep that is harder, or waking in the night for no clear reason.
• Hot flushes, night sweats or palpitations.
• Mood swings, irritability or low mood with no obvious cause.
• Brain fog, worse short-term memory or harder concentration.
• Dry skin, hair loss, or weight gain around the abdomen with unchanged habits.

Having one or more of these is information, not a reason to panic, and it cannot replace a medical diagnosis.

What do the doctors and guidelines say?

• Dr Mary Claire Haver: perimenopause is a critical window for intervention.
• Prof. Unnop Jaisamrarn: prepare early and see it as an opportunity.
• Thai Menopause Society guideline: hormone therapy should be individualised.

Dr Mary Claire Haver, an American obstetrician-gynaecologist and author of The New Perimenopause, puts the case for acting early:

Perimenopause is a critical window for intervention. It’s when we can take steps to support long-term health outcomes, from preventing osteoporosis and heart disease to preserving brain function and quality of life.

Dr Mary Claire Haver · Perimenopause and the Zone of Chaos, 11 July 2025

In Thailand, Prof. Unnop Jaisamrarn, president of the Asia Pacific Menopause Federation, told Matichon that menopause should be seen as a new opportunity to look after yourself, because preparing early helps people pass through it with confidence and lowers the risk of chronic disease (Matichon Online, 24 October 2025, in Thai; translated by us).

The Thai Menopause Society’s 2023 clinical guideline, co-authored by Jaisamrarn U among others, states that menopausal hormone therapy “remains the most effective treatment for vasomotor symptoms and genitourinary syndromes of menopause” and “is effective in preventing bone loss and fractures in postmenopausal women”, but that “hormone therapy should be individualized” by type, dose, route, duration and progestogen use (Journal of Menopausal Medicine, 2024). Whether it is right for you is a decision to make with a specialist, not from an online article.

How can you build a long-term health foundation?

Because the body’s systems change together, care works best when it is joined up. Our three pillars, graded by evidence:

For the sleep and brain pillar, read how to protect your brain as you age.

What should you ask your doctor?

• Are my symptoms consistent with perimenopause, and what else could explain them?
• Which tests, if any, make sense for me at my age?
• What can I do now to protect my bones, heart and brain?
• If hormone therapy is an option, what are the benefits and risks for me?

Bring your symptom diary and your family history, including any bone fractures, early heart disease or dementia.

What should you do this week?

If you do only one thing, record your cycle and symptoms for one week, in an app or a notebook. It helps separate ordinary stress from signs of perimenopause, and it makes your next appointment far more useful.

• Write down the date, the length of your last few cycles and any change in sleep or mood.
• Book a gynaecology appointment if you are 35 or older and noticing changes.
• Ask whether a bone-health or cardiovascular check suits your age and family history.

Frequently asked questions