By Dr Mandy Leonhardt, GP and leading Menopause Specialist. Dr Leonhardt holds the British Menopause Society Certificate of Menopause Care and co-authored The Complete Guide to Premature Ovarian Insufficiency and Early Menopause. Dr Leonhardt is certified as an Advanced Practitioner by the International Society of Gynaecological Endocrinology (ISGE) and is a member of the SISTERLY Expert Panel.
Both premature ovarian insufficiency (POI) and early menopause are serious medical conditions and they are far more common than most people realise, with up to 12 in 100 women experiencing an early menopause between the age of 40 and 45. ¹
Key Takeaways
- Around 4 in 100 girls and women have POI, and up to 12 in 100 women experience an early menopause between the age of 40 and 45.
- POI is diagnosed in a woman under 40 who has stopped her periods for more than 4 months or has very few and very infrequent periods, plus one single raised FSH level above 25 IU/L.
- Around 1 in 4 women with POI don't get any of the classic symptoms, so you should always get tested if your periods stop for 4 months or longer.
Early menopause and POI are more common than most people realise
Most of us think of menopause as something that happens around 51. So when periods start changing in your thirties, or even earlier, it can knock you sideways. If that's you, I want you to know two things straight away: you're not imagining it, and you're not alone.
There are two terms you'll hear. Early menopause is when you only get very few periods (< 3 - 4 per year) or your periods stop completely before the age of 45. Premature ovarian insufficiency (POI) is when your ovaries either never worked properly, from a young age of 11 onwards or they stopped working as they should before the age of 40. Both POI and early menopause are serious medical conditions and they are far more common than most people realise. Around 4 in 100 girls and women have POI, and up to 12 in 100 women experience an early menopause between the age of 40 and 45.
Low oestrogen from POI affects far more than your periods
Basically, when you have POI, your ovaries, which are a pair of hormone producing glands, don’t function as well as they should for your age. Oestrogen is one of the hormones they produce and it plays an important role in normal pubertal development and wellbeing. When ovaries aren’t producing enough oestrogen, you may start to get symptoms. Over time and without treatment, it also affects your long-term health.
In our book, Dr Hannah Short and I describe POI as a "partial or complete loss of ovarian function." I always stress the word "partial." Unlike a typical menopause, the ovaries in POI can still work on and off. Some women find their periods come back for a while. That's why doctors now say "insufficiency" rather than "failure." It's also one reason POI can be confusing, both for women and for the medical professionals trying to diagnose it. Other medical conditions like PMOS can also cause periods to stop and these conditions need to be ruled out as well. ¹
One of the main problems with POI is ongoing low oestrogen and this affects far more than your periods. In the long term this can increase the risks of:
- Bone thinning: osteopenia and osteoporosis, which can lead to fractures
- Heart problems: heart disease and stroke, because oestrogen helps protect your blood vessels and cholesterol
- Brain and mood changes: low oestrogen affects mood and memory, and there may be a higher risk of dementia if POI is left untreated for a long time
- Vaginal and urinary symptoms: dryness, painful sex and urinary problems, which can get worse without treatment
That sounds a lot, I know, but with the right treatment and management, you can protect your health and live as well as peers of your age.
A single raised FSH level can now diagnose POI in women under 40
Based on the latest 2024 ESHRE guidelines, POI is diagnosed in a woman under 40 who has:
- Stopped her periods for more than 4 months or who has very few and very infrequent periods; and she may also have symptoms of oestrogen deficiency
- One single raised FSH (follicle-stimulating hormone) level >25 IU/L
In the past, we needed to have two raised FSH levels, but since 2024, the diagnosis can be made with just one raised FSH level. An AMH test (the "egg reserve" test you may have heard of) isn't routinely used to diagnose it either. If there's any doubt, your GP should refer you to a specialist in menopause or reproductive medicine. Many women also have a baseline bone mineral density (DEXA) scan to check their bone health. Your doctor may suggest other tests to look for an underlying cause. ²
Most women never find a cause, so know the signs to look out for
The honest answer is that for most women, we never find a cause. Not knowing why this is happening to you can be extremely frustrating and demoralising. When there is a known cause, it's usually one of these:
- Medical treatment: surgery to remove the ovaries, chemotherapy or radiotherapy
- Autoimmune conditions: the immune system mistakenly attacks and damages the ovaries
- Genetics: chromosomal conditions such as Fragile X -syndrome or Turner syndrome. Early menopause can also run in families, so it's worth asking your mum or sisters how old they were when their periods stopped.
- Infection: in rare cases, mumps, tuberculosis or malaria
The biggest clue is a change in your periods. They might come less often, instead of every month, you may only have them a few times a year or they may stop completely. You should always get tested if your periods stop for 4 months or longer. You might also notice symptoms related to low oestrogen:
- Hot flushes and night sweats
- Poor sleep and feeling very fatigued and exhausted
- Low mood, anxiety or brain fog
- Vaginal dryness, a lower libido or UTIs that keep coming back
- Achy joints, headaches or palpitations
Around 1 in 4 women with POI don't get any of the classic symptoms. So please don't wait for hot flushes before you take a change in your cycle seriously. If you're under 45 and your periods are less frequent or have stopped, see your GP. Getting checked early and receiving the right diagnosis is the first step to get treatment and to protect your future health.
How to look after yourself
1. Talk to your GP about HRT. HRT, or a combined contraceptive pill, is the main treatment. For women with POI, it's recommended until at least 51, the average age of natural menopause. It isn't only about symptoms. It's replacing hormones your body would normally still be making, and that protects your bones and your heart. If you're in Ireland, HRT has been free at participating pharmacies since June 2025 for anyone with a medical card or a Drugs Payment Scheme card.
2. Eat well and keep moving. What's on your plate really counts when oestrogen drops early:
- Calcium and vitamin D for bones: dairy or fortified plant milks, tinned sardines, calcium-set tofu and leafy greens. Vitamin D is hard to get from food and sun, so a supplement makes sense.
- Protein for muscle and bone strength: fish, eggs, Greek yoghurt, beans and lentils, ideally at every meal.
- Omega-3 and fibre for your heart: oily fish twice a week, plus oats, wholegrains, beans, fruit and veg.
Pair this with regular weight-bearing exercise, like brisk walking, dancing or strength training, to keep your bones strong.
To help fill the gaps, I recommend SISTERLY The Elevator, a daily sachet of 23 nutrients. The Elevator brings together the key nutrients women need during menopause in one daily sachet. Magnesium and selenium support thyroid health and metabolism, and chromium helps steady blood sugar and those sugar and alcohol cravings. B vitamins support mood and energy, while zinc, magnesium and B6 work together on hormone balance. Magnesium also helps calm the mind and muscles for better sleep. For hair, skin and that menopausal dryness, biotin, vitamin C (for collagen) and vitamins A and E help keep you glowing, so you can embrace this new chapter feeling your best.
3. Let yourself feel it. Hannah and I gave whole chapters of our book to grief, identity, relationships and fertility, because this goes so much deeper than hormones. It's completely normal to feel a sense of loss, especially if you were hoping for a pregnancy in the future. Talking to someone, whether that's a friend, a counsellor or your GP, is part of looking after yourself. Because the ovaries can still work on and off, a small number of women with POI do conceive naturally. So talk to your doctor about fertility and contraception.
The bottom line
Early menopause and POI are more common than most of us realise, and the sooner a diagnosis is made, the better you can protect your health in the long term. If something feels off with your cycle, trust your gut, book in with your GP and ask all the questions. You deserve answers.
References
- Leonhardt, M. and Short, H. (2022). The Complete Guide to POI and Early Menopause: Practical Advice and Support for Living with Early Menopause and POI. Sheldon Press.
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ESHRE, ASRM, CRE-WHiRL, IMS (2024). Evidence-based guideline: Premature Ovarian Insufficiency. European Society of Human Reproduction and Embryology.
