Last reviewed: October 2026
When women think of menopause, they usually picture hot flushes and periods stopping. But the years leading up to menopause, called perimenopause, can start with changes that are much easier to miss or to blame on something else. Knowing what to look for can help.
What is perimenopause?
Menopause is your last menstrual period. It is only confirmed in hindsight, after 12 months without a period. In Australia, the average age of menopause is around 51.
Perimenopause is the lead-up. It often begins in your 40s and can last anywhere from a few months to several years. During this time, hormone levels, especially oestrogen and progesterone, do not simply fall in a straight line. They rise and fall unpredictably, sometimes from week to week. That up-and-down pattern helps explain why symptoms can come and go and can feel confusing.
Signs that are easy to miss
Not everyone gets all of these, and each one can have other causes. But together, especially in your 40s, they may point to perimenopause.
Changes to your cycle. Often the first sign. Cycles may get shorter (for example, every three weeks instead of four), then later become longer or irregular. Evidence: strong. Cycle changes are the basis of the internationally used STRAW+10 staging system.
Heavier or longer periods. Many women expect periods to get lighter, but heavier bleeding, flooding or passing clots is common in perimenopause. Evidence: strong that it is common. It still needs checking (see below).
Poor sleep. Trouble falling asleep, waking at 3 am, or night sweats that disturb sleep. Evidence: strong that sleep problems become more common during the menopause transition.
Mood changes and anxiety. New or worse anxiety, irritability, low mood or feeling “not yourself”, sometimes without hot flushes. Evidence: moderate to strong. The risk of depressive symptoms appears to rise during perimenopause, especially for women with a past history of depression or premenstrual mood symptoms.
Brain fog. Forgetting words, losing your train of thought, or finding it harder to concentrate. Evidence: moderate. A large US study (SWAN) found a small, measurable dip in learning and memory during perimenopause that tended to recover after menopause. It is real, and for most women it appears to be temporary.
Joint and muscle aches. Stiffness and aches without an obvious injury are commonly reported. Evidence: emerging. The link is seen in surveys and observational studies, but how much is due to hormones versus ageing or other factors is uncertain.
Heart palpitations. A racing, pounding or fluttering heartbeat, sometimes with hot flushes. Evidence: moderate that palpitations are common at this stage. However, palpitations should never just be assumed to be hormonal, so it is worth getting them checked.
Other changes. Vaginal dryness, needing to pass urine more often, headaches or migraines that change pattern, and lower interest in sex are also common.
Do I need a blood test to diagnose perimenopause?
Often, no. This surprises many women.
Because hormone levels swing so much during perimenopause, a single blood test can look “normal” one week and quite different the next. For this reason, both the UK’s National Institute for Health and Care Excellence (NICE) and the Australasian Menopause Society advise that, for women aged 45 and over with typical symptoms, perimenopause and menopause are usually diagnosed from symptoms and cycle changes, not hormone blood tests. Evidence: strong guideline consensus.
Blood tests can still be useful in some situations, for example:
- if you are under 45, and especially under 40
- if your symptoms are unusual
- to rule out other causes such as thyroid problems, low iron or anaemia, especially if bleeding is heavy.
So if you have been told your hormone tests were “normal”, that does not rule out perimenopause.
When to see a health practitioner promptly
Some symptoms should be checked rather than put down to “just hormones”. Please see a GP or health practitioner if you have:
- bleeding after sex
- bleeding between periods
- very heavy bleeding, such as soaking through a pad or tampon every hour or two, flooding, or feeling dizzy, tired or short of breath
- any bleeding after your periods have stopped for 12 months
- palpitations with chest pain, fainting or shortness of breath
- low mood that is severe, or any thoughts of harming yourself.
If you are having chest pain, fainting or any other emergency, call 000. For mental health crisis support, you can call Lifeline on 13 11 14.
Keeping it in perspective
Perimenopause is a normal life stage, not an illness. Some women barely notice it. Others find it affects their work, relationships and wellbeing. Both experiences are valid.
Simple steps such as keeping a symptom and cycle diary for two to three months can make a conversation with your practitioner much more productive. There is a range of options for managing symptoms, from lifestyle changes to medical treatment, and the right choice depends on your symptoms, health history and preferences. A good starting point is an honest conversation with a practitioner you trust.
References
- National Institute for Health and Care Excellence. Menopause: identification and management (NG23). Published 2015, last updated April 2026. https://www.nice.org.uk/guidance/ng23
- Harlow SD, Gass M, Hall JE, et al. Executive summary of the Stages of Reproductive Aging Workshop + 10: addressing the unfinished agenda of staging reproductive aging. Menopause. 2012;19(4):387–395. https://doi.org/10.1097/gme.0b013e31824d8f40
- Santoro N. Perimenopause: from research to practice. Journal of Women’s Health. 2016;25(4):332–339. https://doi.org/10.1089/jwh.2015.5556
- Greendale GA, Huang MH, Wight RG, et al. Effects of the menopause transition and hormone use on cognitive performance in midlife women. Neurology. 2009;72(21):1850–1857. https://doi.org/10.1212/WNL.0b013e3181a71193
- Hickey M, LaCroix AZ, Doust J, et al. An empowerment model for managing menopause. The Lancet. 2024;403(10430):947–957. https://doi.org/10.1016/S0140-6736(23)02799-X
- Australasian Menopause Society. Consumer fact sheets. https://www.menopause.org.au/consumer-information/fact-sheets/
- healthdirect Australia. Perimenopause. https://www.healthdirect.gov.au/perimenopause
This article is general information only and is not a substitute for individual medical advice. Talk to your health practitioner about your own situation.