Premature ovarian failure (POI): causes and care

The ovaries release eggs and make oestrogen and other hormones. In premature ovarian failure the ovaries stop doing this reliably before the age of 40. Many specialists now prefer the term premature ovarian insufficiency (POI), because ovarian function can come and go and does not always stop completely.

The NHS uses the terms early and premature menopause. It says menopause is when periods stop due to lower hormone levels and usually affects women between 45 and 55. Early menopause is before 45 and premature menopause is before 40. The Daisy Network, a UK support charity for women with POI, describes POI as typically occurring before 40 and characterised by reduced or absent ovarian function.

The NHS says the main symptom is not having periods regularly, or periods stopping completely, before the age of 45. The Daisy Network adds that periods can suddenly become lighter or less frequent, and that teenagers who have not started periods by the age of 15 may be affected.

• Hot flushes and night sweats.

• Vaginal dryness, and pain during sex.

• Difficulty sleeping.

• Low mood, anxiety and mood swings.

• Reduced sex drive.

• Problems with memory or concentration, often called brain fog.

• Difficulty getting pregnant.

The Daisy Network explains that POI is often mistaken for stress, lifestyle factors, polycystic ovary syndrome or psychological problems, particularly in younger women and teenagers. Because it is relatively rare and unexpected under 40, it may not be considered early, and symptoms can fluctuate, so a clear diagnosis may take time.

This matters because early recognition helps protect bone health, supports fertility planning and emotional wellbeing. If you are under 40 and have irregular periods or menopausal symptoms, speak to a GP. The NHS says a GP may sometimes do blood tests if you are under 45 and having menopause symptoms.

The Daisy Network says that in most cases the cause remains unknown, with around 90% diagnosed as idiopathic or spontaneous POI. It adds that not knowing the cause can be hard emotionally, but treatment and support do not depend on it.

Where a cause is found, it may be autoimmune, where the immune system attacks the ovaries and may also affect the thyroid, pancreas or adrenal glands; genetic, such as Turner syndrome or a fragile X premutation, particularly when diagnosed very young; surgical, after both ovaries are removed; or cancer treatment, especially pelvic radiotherapy and chemotherapy. Rare infections such as mumps have also been linked.

The NHS says you have a higher chance of early or premature menopause if it runs in your family, and that it is more likely if you started periods early, smoke or are underweight. It can also follow radiotherapy, chemotherapy, certain hormone medicines or surgery to remove the ovaries.

The Daisy Network says diagnosis involves medical history, symptoms and blood tests. For women under 40 the criteria are absent periods, or infrequent periods for at least four months, plus a blood test showing high follicle stimulating hormone (FSH) above 25 IU/L. If unclear, the FSH test is repeated after 4 to 6 weeks.

FSH rises because the brain tries to push the ovaries to respond. Persistently high FSH is a sign that the ovaries are no longer working efficiently. Other tests may check the thyroid, look for autoimmune conditions or assess chromosomes, particularly in younger women. A bone density scan may be arranged.

Getting a diagnosis can be a shock, particularly for someone who hoped to have children. Ask whether counselling is available.

The NHS says the main treatments are medicines such as the combined contraceptive pill or hormone replacement therapy (HRT) to replace low hormones. It says it is important to replace missing hormones if menopause started before 45, because there is a higher chance of problems with bones and the heart. Women who have had certain cancers, such as some breast cancers, may not be able to have hormone treatments.

Lifestyle measures matter too. The NHS suggests regular exercise and calcium-rich foods such as yoghurt. If symptoms persist despite treatment, referral to a specialist menopause centre is possible, and the NHS points to the British Menopause Society website for finding NHS or private specialists.

The Daisy Network says that after surgical removal of both ovaries menopausal symptoms may start suddenly, so starting HRT soon after surgery should be discussed with the medical team. The type and dose of hormones should be agreed with a clinician who knows your history.

The NHS says early or premature menopause can affect physical and mental health, and gives a higher chance of osteoporosis and cardiovascular disease. Because of this, long-term follow-up with a GP or specialist is valuable, including a review of whether hormone treatment is working.

The NHS notes that mental health help is available, and you can get NHS talking therapies without seeing a GP first. Support groups such as the Daisy Network offer information and peer contact, which many women find helpful after a diagnosis that can feel isolating.

The NHS says early or premature menopause means you may find it harder to get pregnant, and that you may be able to have children through IVF using your own frozen eggs or donor eggs. Surrogacy and adoption are other routes.

The Daisy Network says natural conception is uncommon and unpredictable, but around 5 to 10% of women may conceive naturally, particularly early after diagnosis. There are no proven treatments to restore fertility, and a fertility specialist can assess ovarian reserve. For women at risk of POI before cancer treatment, it says egg, embryo or ovarian tissue freezing should be discussed as early as possible, because these techniques work best before ovarian function declines.

Contraception may still be needed if pregnancy is not wanted, and a clinician can advise because hormone treatments differ in whether they prevent pregnancy.