The average age of menopause is around 51. But for a meaningful minority of women it comes much earlier — and when it does, the implications reach well beyond the symptoms.
The terms
- Premature ovarian insufficiency (POI), sometimes called primary ovarian insufficiency, is when the ovaries stop working normally before age 40. It affects roughly 1% of women.
- Early menopause describes menopause between 40 and 45, affecting around 5% of women.
- Induced menopause happens immediately when both ovaries are surgically removed, or when chemotherapy or radiation damages them.
POI is not quite the same as menopause. Ovarian function can be intermittent: some women with POI still have occasional periods, and a small percentage conceive naturally after diagnosis. That’s one reason doctors prefer the term “insufficiency” over “failure”.
What causes it
In most women with POI, no cause is ever found. Known causes include:
- Genetic factors, including a premutation in the FMR1 gene (linked to fragile X syndrome) and Turner syndrome
- Autoimmune conditions, where the immune system attacks ovarian tissue — often alongside thyroid disease or other autoimmune disorders
- Cancer treatment, especially certain chemotherapy drugs and pelvic radiation
- Surgery on or removal of the ovaries
- Family history — early menopause in a mother or sister raises the likelihood
Smoking is associated with menopause arriving one to two years earlier on average.
Symptoms
The symptoms resemble menopause at any age: irregular or stopped periods, hot flashes, night sweats, vaginal dryness, poor sleep, low mood and difficulty concentrating. Because women in their 20s and 30s don’t expect them, the symptoms are often attributed to stress, birth control or eating patterns, and diagnosis can be delayed for years.
How it’s diagnosed
A clinician will usually check follicle-stimulating hormone (FSH) and estradiol levels, typically twice, several weeks apart. Persistently high FSH with low estrogen in a woman under 40 who has missed periods for several months points to POI. Further tests often include thyroid function, prolactin, and genetic testing for the fragile X premutation and chromosomal causes.
Why it matters for long-term health
Estrogen does far more than regulate periods. Losing it early means more years without its protective effects:
- Bone. Bone loss starts earlier, raising the long-term risk of osteoporosis and fractures.
- Heart. Early menopause is associated with higher risk of cardiovascular disease.
- Brain. Some studies link early surgical menopause with higher risk of cognitive decline later in life.
- Mood. Rates of depression and anxiety are higher, sometimes linked to the shock of the diagnosis itself.
Treatment
For women with POI or early menopause, hormone replacement is usually recommended until around the average age of natural menopause, unless there’s a specific reason not to. This is an important distinction from hormone therapy at 55 or 60: here, the goal is largely to replace what the body would normally still be making, protecting bone and heart health as well as treating symptoms. Major menopause and endocrinology societies support this approach.
Women with a history of hormone-sensitive cancer need individual advice, and non-hormonal treatments for symptoms and bone protection are available.
Fertility
For many women, the hardest part of POI is its impact on fertility. Spontaneous pregnancy is possible but uncommon. Egg donation offers good chances of pregnancy for many women with POI. Women facing cancer treatment can ask about fertility preservation — egg or embryo freezing — before treatment begins.
Getting support
A diagnosis of POI can bring grief, confusion and isolation, particularly for women who hadn’t finished building a family. Specialist menopause clinics, counselling and peer support groups can help. If periods stop for three months or more before 40, or you develop menopausal symptoms early, ask for testing — an early diagnosis means earlier protection for bones and heart.