Hormones & HRT - Menopause
Perimenopause and menopause, explained
Last updated 30 September 2026. How we write this .
Menopause is your last period, confirmed after 12 months without one. Perimenopause is the run-up, often lasting years, when hormones swing and symptoms such as hot flushes, poor sleep and low mood begin.
Start here Menopause is your last period, confirmed after 12 months without one. Perimenopause is the run-up, often lasting years, when hormones swing and symptoms such as hot flushes, poor sleep and low mood begin.
By the end, you will understand What is happening in the body? What are the first signs of perimenopause? How long do symptoms last? Key words used in this lesson Meta-analysis A statistical method for combining the results of multiple studies into a single estimate. More reliable than any one study, but bounded by the quality of what went into it. Full plain-English glossary
Where this information comes from Claim-cited evidence. Central research claims on this lesson are linked to specific studies or official guidance.
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Menopause is the point when periods stop for good, and it is only recognised looking back, once you have gone 12 months without a period while not using hormonal contraception. Perimenopause is the stretch before it, when periods become irregular and symptoms often start. After that 12-month mark you are postmenopausal. In the UK this usually happens between 45 and 55, though it can come earlier, and it affects anyone who has periods.
The experience varies enormously. The NHS notes that some people barely notice it, while others find it affects their work, sleep, relationships and mood for years.
What is happening in the body?
Periods change and eventually stop because the ovaries make less oestrogen and progesterone. The fall is not smooth. During perimenopause hormone levels lurch up and down before settling low. The Penn Ovarian Aging Study, which followed women in Philadelphia for 8 years, found that oestradiol and follicle-stimulating hormone (FSH), the signal the brain sends to prod the ovaries, swung more widely around each woman's own average as she moved through the transition.
Those swings help explain why symptoms can come and go, and why one blood test often says little. Lower oestrogen reaches well beyond periods. The NHS notes that osteoporosis is common after menopause because oestrogen is needed for healthy bones, and the tissues of the vagina and bladder are affected too.
What are the first signs of perimenopause?
A change in periods is usually the first sign. They may come more or less often, and bleeding may get heavier or lighter. Other common symptoms listed by the NHS and NICE include:
hot flushes and night sweats: sudden waves of heat over the face, neck and chest, sometimes with a racing heart or anxiety trouble getting to sleep or staying asleep, often worse with night sweats low mood, anxiety, mood swings, poor memory or brain fog vaginal dryness, itching or pain during sex, and more urine infections or needing to pee more often joint and muscle aches, headaches that are worse than usual, and a lower sex drive Hormonal contraception can hide the picture, because it changes or stops bleeding. It is still possible to get pregnant during perimenopause. The NHS advises keeping contraception for 2 years after your final period if you are 40 to 49, and for 1 year if you are 50 or over.
How long do symptoms last?
Longer than many people are told. The Study of Women's Health Across the Nation (SWAN) followed 3,302 women in the United States through the transition. Among the 1,449 who had frequent hot flushes or night sweats, the median total duration was 7.4 years, and symptoms carried on for a median of 4.5 years after the final period. Women whose symptoms began early, while their periods were still regular or only starting to change, had them for a median of more than 11.8 years. African American women reported the longest duration, a median of 10.1 years. The NHS similarly says symptoms usually last 7 to 9 years, sometimes longer, and notes that women from a Black ethnic background are more likely to have severe and longer-lasting hot flushes.
Symptoms also change shape over time. Hot flushes may fade while low mood or anxiety become more noticeable. Some symptoms, such as joint pain and vaginal dryness, can continue after menopause.
Is it the menopause or is it depression?
It can be both, and low mood becomes more common during the transition. The Penn Ovarian Aging Study looked only at women with no history of depression. During the menopause transition, high scores on a depression questionnaire were more than 4 times as likely as before it, and a diagnosed depressive disorder was 2.5 times as likely, even after allowing for hot flushes, poor sleep and other factors. Changing FSH and oestradiol levels were linked to these symptoms.
This is the area where the evidence is least settled. Studies like this show a link, and it is hard to separate the effect of hormones from broken sleep and the ordinary pressures of midlife. What it does mean is that new low mood in your 40s or 50s deserves to be taken seriously and talked about, not brushed off. NICE suggests HRT or CBT for depressive symptoms that start around the same time as other menopause symptoms, and standard depression care where depression is diagnosed.
Do I need a blood test, and what if it happens early?
Usually not, if you are 45 or over. NICE advises that perimenopause and menopause are identified from symptoms and period changes alone in otherwise healthy people of that age, and it recommends against hormone tests such as oestradiol or anti-Mullerian hormone in that age group. An FSH test may be considered between 40 and 45, and for anyone under 40 in whom menopause is suspected.
Menopause before 45 is called early menopause, and before 40 premature ovarian insufficiency (POI). They are not rare. A 2019 meta-analysis of 31 studies estimated that POI affects 3.7% of women and early menopause 12.2%. The NHS says the chance is higher if it runs in the family, if you started periods early, smoke or are underweight, and after chemotherapy, radiotherapy or surgery to remove the ovaries. NICE says POI should be diagnosed from symptoms plus raised FSH on 2 blood samples taken 4 to 6 weeks apart, never a single test. Because early loss of oestrogen raises the risk of osteoporosis and heart disease, NICE advises hormone replacement, either HRT or a combined contraceptive pill, until at least the usual age of menopause unless there is a reason not to.
What helps?
NICE recommends offering HRT for hot flushes and night sweats, and vaginal oestrogen for vaginal and urinary symptoms; our separate lesson on HRT covers the benefits and risks. For people who cannot take HRT or prefer not to, there are other options. Cognitive behavioural therapy (CBT), a structured talking therapy, has trial evidence. In the MENOS 2 trial, run from King's College London, 140 women with at least 10 troublesome hot flushes or night sweats a week were given group CBT, self-help CBT or no treatment. After 6 weeks, both CBT groups rated their flushes about 2 points less of a problem on a 10-point scale than the untreated group, and had fewer night sweats. The benefit was smaller but still present at 26 weeks. NICE now recommends menopause-specific CBT for hot flushes, sleep problems and low mood.
Day-to-day changes help too. The NHS suggests light layers, a cool bedroom, and cutting back on triggers such as spicy food, caffeine, alcohol and smoking. Weight-bearing exercise such as walking or dancing helps protect bones, and NICE stresses keeping up muscle strength through activity. Vaginal moisturisers and lubricants are sold in pharmacies without a prescription.
See a GP if symptoms are affecting your life, if you are under 45 and think you have menopause symptoms, or if your periods become heavier rather than lighter. Any vaginal bleeding after 12 months without a period, even a single episode of spotting, needs checking by a GP, because occasionally it is a sign of cancer.
This lesson is general education about menopause, not medical advice. For questions about your own symptoms or treatment, speak to your GP, practice nurse or pharmacist.
Related in this classroom Related in other classrooms The studies behind this page Menopause: identification and management. Recommendations - NICE guideline NG23, updated 2024, amended April 2026Symptoms of menopause and perimenopause - NHSEarly or premature menopause - NHSThings you can do to help menopause and perimenopause symptoms - NHSDuration of menopausal vasomotor symptoms over the menopause transition (SWAN) - JAMA Internal Medicine, 2015Associations of hormones and menopausal status with depressed mood in women with no history of depression - Archives of General Psychiatry, 2006The global prevalence of primary ovarian insufficiency and early menopause: a meta-analysis - Climacteric, 2019Effectiveness of group and self-help cognitive behavior therapy in reducing problematic menopausal hot flushes and night sweats (MENOS 2): a randomized controlled trial - Menopause, 2012Sources for this classroom
Educational content only. Not medical advice, diagnosis or treatment. Always consult a qualified healthcare professional before changing your health regimen.