Skip to main content

Warning notification:Warning

Unfortunately, you are using an outdated browser. Please, upgrade your browser to improve your experience with HSE. The list of supported browsers:

  1. Chrome
  2. Edge
  3. FireFox
  4. Opera
  5. Safari

Overview - Polycystic ovary syndrome (PCOS)

Polycystic ovary syndrome (PCOS) is a common condition that affects how your ovaries work.

It can impact your:

  • hormones
  • periods
  • fertility
  • long-term health

Polycystic ovaries

Polycystic ovary syndrome does not mean you have cysts on your ovaries.

Polycystic ovaries are slightly larger than normal ovaries and contain many follicles. Follicles are small fluid-filled sacs that release an egg when you ovulate.

In PCOS, these sacs are not usually able to release an egg. This means that you may not ovulate each month.

Many women have polycystic ovaries without having PCOS. Ovaries that appear polycystic are normal in teenagers.

Symptoms of PCOS

Symptoms can include:

Symptoms of PCOS

Causes of PCOS

The exact cause of PCOS is not known.

It may run in your family.

The 2 main problems that may cause PCOS are:

  • insulin resistance
  • hormone imbalance

Causes of PCOS

Diagnosing PCOS

You may be diagnosed with PCOS if you're an adult and have at least 2 of the following:

  • irregular periods, infrequent periods or no periods at all
  • excess hair growth on your face or body or high levels of testosterone in your blood
  • an ultrasound scan that shows you have polycystic ovaries

Diagnosing PCOS

Treating PCOS

There's no cure for PCOS. But you can manage the symptoms.

You can improve symptoms and long-term health problems by making lifestyle changes.

There are also medicines for treating PCOS symptoms such as:

  • excess hair growth
  • irregular periods
  • fertility problems

With treatment, most women with PCOS are able to get pregnant.

Treatment for PCOS

Health risks in the future

Having PCOS increases your chances of developing other health problems in the future.

For example, women with PCOS have a higher chance of developing:

Non-urgent advice: Contact your GP if:

  • you have less than 4 periods a year

You can reduce your chances of getting endometrial cancer by using treatments that help you get a regular period.

For example:

  • the contraceptive pill
  • progesterone tablets

PCOS and fertility

PCOS can be a cause of fertility problems. But you may still become pregnant even if you do not have periods.

PCOS increases your chance of:

To reduce your risk of complications:

Pregnancy risks and PCOS


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

Page last reviewed: 25 February 2025
Next review due: 25 February 2028

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