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Diagnosis - Polycystic ovary syndrome (PCOS)

Talk to your GP if you have any symptoms of polycystic ovary syndrome (PCOS).

You will be asked about your symptoms. Your GP may also check your blood pressure. This will help rule out other possible causes.

They will need to ask you questions about your periods such as:

  • what age you were when you first got your period
  • if you get one every month
  • if you have painful or heavy periods

They might also ask you if you have noticed weight gain, excessive hair growth, hair loss or acne.

Read about the symptoms of PCOS

Tests for PCOS

If your GP thinks you may have PCOS you might need some tests done. This is to confirm the diagnosis. It is also to check for other causes of hormone imbalance.

Your GP may also weigh you and examine you.

Blood test

You may have blood tests done to check your hormone levels. If you have PCOS you might have higher levels of the male hormone (testosterone) than usual. You might also have a higher LH/FSH ratio of a hormone called LH (lutenising hormone).

Your GP might also recommend other blood tests. They might advise you to have screening for diabetes or to have your cholesterol levels checked.

Ultrasound scan

Your GP might refer you for an ultrasound scan. Ultrasound scans aren't painful. They use sound waves to create pictures of parts of the body on a TV screen. If you have PCOS, an ultrasound scan may pick up certain features of PCOS. These include having lots of follicles at the edge of your ovaries that may look bigger than usual (polycystic ovaries). The follicles are fluid-filled sacs in which eggs develop.

Not everyone with polycystic ovaries on the ultrasound scan has PCOS. Up to a third of young women will have polycystic ovaries on an ultrasound scan. But their periods and hormone levels are normal meaning they do not have PCOS.

Read more about polycystic ovaries

Diagnosis criteria

A diagnosis can usually be made if other rare causes of the same symptoms have been ruled out.

You will also need to meet at least 2 of the following 3 criteria

  • You have irregular or infrequent periods, or no periods at all.
  • You have increased hair growth on your face or body, or blood tests show you've higher levels of testosterone than usual.
  • An ultrasound scan shows you have polycystic ovaries.

Only 2 of these need to be present to diagnose PCOS. You may not need to have an ultrasound scan.

Infrequent periods are when you get your period less than 6 to 8 times a year.

Irregular periods are when the length of your menstrual cycles keeps changing. This means the gap between your periods changes and your periods might come early or late.

Missed, early, or late periods are also considered signs of an irregular cycle.

Referral to a specialist

If you have PCOS, your GP will treat you.

They may also refer you to a specialist, especially if you're trying to get pregnant.

This could be:

  • a gynaecologist – a specialist in treating conditions of the female reproductive system
  • an endocrinologist – a specialist in treating hormone problems
  • a fertility specialist

Your GP or specialist will discuss with you the best way to manage your symptoms.

If you are overweight, your GP will talk to you about ways to reduce your weight. They'll recommend lifestyle changes and start you on any necessary medication.


If you have PCOS, you may need to be checked every year for:

  • blood pressure
  • diabetes

This will depend on your age and weight.

Content supplied by the NHS and adapted for Ireland by the HSE

Page last reviewed: 23 March 2021
Next review due: 23 March 2024

This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.