Premature ovarian insufficiency (POI) is when the ovaries stop working normally before age 40, often showing up as irregular or missing periods and reduced fertility. Diagnosis usually needs at least four months of missed or infrequent periods plus repeated high FSH tests. Pregnancy is possible but uncommon, and options include donor eggs. See a clinician if your periods stop or become irregular.
Premature ovarian insufficiency, or POI, means the ovaries are not working normally before age 40. It can bring irregular or missing periods, symptoms like hot flashes, and trouble conceiving. It is a difficult diagnosis to receive, but there is a clear workup, good care for your long-term health, and more than one route to becoming a parent.
What POI Is (and Is Not)
NICHD describes POI as the ovaries stopping normal function before age 40, and it points out that POI is not the same as early or premature menopause. People with POI can still have occasional periods, and ESHRE notes that spontaneous pregnancy, while uncommon, can happen.
ESHRE estimates POI affects about 1 percent of the general population. It is different from simply having a lower egg count for your age, which is the question tested by AMH. See AMH and ovarian reserve and understanding your AMH results for that topic.
Signs and Symptoms
The most common sign is a change in periods: they become irregular, farther apart, or stop. Reduced fertility, sometimes noticed in the teen years or twenties, is another. Because estrogen is low, some people also notice menopause-type symptoms:
- Hot flashes and night sweats.
- Vaginal dryness or discomfort with sex.
- Sleep problems, mood changes, or trouble concentrating.
- Lower interest in sex.
Some people have few symptoms apart from missed periods. NICHD says a provider may order tests if a woman under 40 has irregular periods or has missed periods for four months or longer. Do not assume a missed period is stress, and do not wait for months to ask.
How POI Is Diagnosed
ESHRE’s guideline summary gives these consensus criteria: at least four months of absent or infrequent periods, plus an FSH level above 25 IU/L on two occasions more than four weeks apart. A single high result is not enough, which is why repeat testing matters. The guideline notes that formal diagnostic accuracy studies are lacking, so these criteria reflect expert agreement. Tests ordered for background include a pregnancy test and thyroid and prolactin levels, which rule out other causes of missed periods. Our explainer on day 3 hormone labs shows what FSH, estradiol, and LH tests measure.
ESHRE also recommends looking for a cause once POI is confirmed:
- Chromosome testing (karyotype) for non-treatment-related cases, because conditions such as Turner syndrome can be involved.
- Fragile X premutation testing, with counseling about what a result could mean for family members.
- Autoimmune screening, such as adrenal and thyroid antibodies, when the cause is unknown or an immune disorder is suspected.
In many people no cause is found. Treatments such as chemotherapy, radiation, or ovarian surgery can also cause POI, which is why fertility preservation conversations happen before cancer care. See fertility preservation before cancer treatment.
Looking After Your Health
Low estrogen over a long time can affect more than fertility. NICHD notes a higher risk of osteoporosis, and ESHRE adds that hormone replacement may help protect bone and heart health. According to the ESHRE summary:
- Hormone therapy is recommended to treat low-estrogen symptoms and, for people with POI, is generally continued until at least the average age of natural menopause, unless there are reasons not to.
- People with an intact uterus take a progestogen with estrogen to protect the uterine lining.
- The ESHRE guideline reports that hormone therapy has not been found to increase breast cancer risk before the age of natural menopause.
The right plan, type, and dose are for you and your doctor to decide, and this article does not give dosing. Also ask about bone health, heart health, mood, and sexual health as part of regular follow-up.
Family-Building Options
Hearing "POI" can feel like a door closing. It is more accurate to say the routes change.
If you are diagnosed while still having occasional cycles, ask a reproductive endocrinologist what is realistic for you. Fertility preservation options such as egg freezing depend on ovarian response, and they are time sensitive for people with known risk. Read egg freezing 101 to see how that works in general, and keep in mind that a person with POI may have fewer eggs to retrieve.
The Emotional Side
Grief, anger, and a sense of unfairness are common after a POI diagnosis, especially because it can arrive suddenly and affect plans for children. You may also be navigating hormone symptoms, relationships, and the uncertain path forward at once. Talking with a counselor who understands fertility can help, and our guide to finding a fertility-informed therapist can get you started. Peer support from others with POI can also reduce isolation.
When to see a clinician: if you are under 40 and your periods become irregular or stop for four months or longer, if you have hot flashes or night sweats, or if you have been trying to conceive without success. Our article on when to see a fertility specialist covers the broader signs.
Frequently Asked Questions
The Bottom Line
POI is a real medical condition with a clear path for diagnosis and care. If your periods have become irregular or stopped before 40, ask for testing rather than waiting. Treat your bone and heart health as part of the plan, and talk with a reproductive endocrinologist about the family-building routes that fit your values. You are not alone, and you have more than one way forward.
Want to understand your hormone numbers?
See what FSH, estradiol, and LH tests measure and how clinicians read them together.
Day 3 Hormone Labs Explained →