Premature ovarian insufficiency (POI) happens when the ovaries stop working as expected before the age of 40. The ovaries may not release eggs regularly, and estrogen levels drop earlier than usual.

You might also hear POI referred to as “premature ovarian failure,” though this term is used less often now — because ovarian activity in POI can be inconsistent. Some people still ovulate occasionally, even after diagnosis.

POI is relatively rare, affecting about 1% of women under 40 (Cleveland Clinic).

What Causes POI?

In many cases, the cause isn’t clear. But some known factors include:

• Genetics – conditions such as Turner syndrome or Fragile X premutations.
  
  
• Autoimmune conditions – when the immune system mistakenly attacks ovarian tissue.
  
  
• Cancer treatment – chemotherapy and radiation can damage the ovaries.
  
  
• Ovarian surgery – procedures that remove or injure ovarian tissue.
  
  
• Environmental factors – smoking and certain toxins may increase risk.
  
  
• Family history – relatives with POI or early menopause can raise the likelihood.
  
  

Symptoms of POI

Because ovarian function can fluctuate, symptoms vary. The most common include:

• Irregular or missed periods
  
• Hot flashes and night sweats
  
• Vaginal dryness and discomfort during sex
  
• Low libido
  
• Mood changes, anxiety, or depression
  
• Trouble sleeping
  
• Brain fog or difficulty concentrating
  
• Fertility challenges
  

Low estrogen over time can also lead to bone thinning (osteoporosis) and higher cardiovascular risk.

How is POI Diagnosed?

Doctors use a combination of history, exams, and blood tests to make a diagnosis. The process often includes:

1. Medical history & exam – looking at menstrual patterns, family history, and past treatments like chemotherapy.
   
2. Pregnancy test – to rule out pregnancy as the reason for missed periods.
   
3. Hormone blood tests – checking for high FSH and low estrogen levels, usually more than once.
   
4. Genetic testing – in some cases, to look for chromosomal or inherited conditions.
   
5. Autoimmune screening – if there are signs of immune-related issues.
   
6. Pelvic ultrasound – to check ovarian size and follicle count.
   

The American College of Obstetricians and Gynecologists (ACOG) provides detailed guidelines on how doctors approach diagnosis and management.

Why Early Diagnosis Matters

POI doesn’t just affect fertility — it has a bigger impact on long-term health. Estrogen plays a key role in protecting bones, the heart, and mental wellbeing.

Early diagnosis gives you the chance to:

• Explore fertility preservation or assisted reproduction options
  
• Start hormone therapy if recommended
  
• Protect bone and heart health with lifestyle and medical support
  
• Access emotional and psychological support
  

What to Do if You Suspect POI

If you’re under 40 and your periods have stopped, become very irregular, or you’re experiencing symptoms like hot flashes, it’s worth checking in with your doctor.

A reproductive endocrinologist or gynecologist can run tests, rule out other causes, and guide you on next steps.

The Bottom Line

Premature ovarian insufficiency is when the ovaries stop functioning normally before age 40. While it can be overwhelming to face, early diagnosis helps you take action — both for fertility and long-term health.

If your cycle feels “off,” don’t ignore it. Getting checked is the first step toward understanding your body and protecting your future health.

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