Polycystic ovary syndrome (PCOS)

Expert reviewer Dr Robin Crawford, Consultant Gynaecologist
Next review due March 2019

Polycystic ovary syndrome (PCOS) is a condition that affects the way your ovaries work. Your ovaries may have lots of small cysts or follicles (small, fluid-filled lumps or pockets) on them and they may be larger than usual too. In the UK, about seven in every 100 women have PCOS.

More about polycystic ovary syndrome

Women have two ovaries, which are small organs that are part of your reproductive system. Eggs (ova) mature here and are released about once a month. This is called ovulation. Your ovaries also produce the hormones (chemicals) oestrogen, progesterone and testosterone.

Before ovulation, the egg develops in a small swelling on your ovary called a follicle before it’s released. A number of follicles begin to develop but only one will become a fully mature egg. If you have polycystic ovary syndrome (PCOS), lots more follicles than usual start to grow, but none of these develop into an egg for ovulation. You’ll usually have more than 12 follicles on your ovary. These follicles become cysts that stay on your ovaries.

If you have PCOS, you will usually have two or three of the following.

  • A higher level of testosterone than usual.
  • Release eggs from your ovaries irregularly, or not at all.
  • Have lots of cysts on your ovaries.

Having cysts on your ovaries doesn't always mean you have PCOS; in fact, about two in 10 women have them without having PCOS. You can also have PCOS without having any cysts on your ovaries.

An image showing an ovary affected by polycystic ovary syndrome

Symptoms of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) tends to affect women differently but your symptoms may include:

  • having irregular periods, sometimes less than eight a year, or none at all
  • problems with your fertility (you need to ovulate to become pregnant and you may not be ovulating regularly or at all)
  • being overweight
  • having more hair than usual on your face, or on your back, chest or shoulders for example – the medical name for this is hirsutism
  • thinning hair on top of your head
  • oily skin or acne
  • patches of dark thick skin in your armpit or around your groin or neck
  • a problem called sleep apnoea that can affect how you sleep

You’ll usually start to get symptoms when you reach puberty and these should go when you enter the menopause.

Diagnosis of polycystic ovary syndrome

Your GP will ask about your symptoms and examine you, and will ask you about your medical history.

Your GP will look for any signs of polycystic ovary syndrome (PCOS) and rule out any other conditions that can cause similar symptoms. You might need to have some of the tests below too.

  • Blood tests to check for things like how well your thyroid gland is working. This is important because if you have problems with your thyroid gland, it can cause symptoms that are similar to PCOS. The levels of glucose and hormones, such as testosterone, in your blood may also be measured.
  • An ultrasound scan to see if you have cysts on your ovaries. You might need to have a transvaginal ultrasound, which means the ultrasound probe will be put into your vagina. And you might have an abdominal ultrasound and your radiographer will pass the probe over your tummy too.

If your GP thinks you may have severe PCOS or problems with infertility, they’ll refer you to see a specialist doctor. This may be a gynaecologist, who specialises in women's reproductive health, or an endocrinologist, who specialises in the body's hormonal system.

Treatment of polycystic ovary syndrome

There isn’t a cure for polycystic ovary syndrome (PCOS), but there are lots of treatments that can help to control your symptoms. These include treatments for excess hair and acne, as well as treatments to improve your fertility.

You might need to take treatments to control your symptoms until you reach the menopause. These should then improve and you probably won’t need any treatment beyond that point.

Self-help treatments

If you make some changes to your lifestyle, it may help to control your symptoms. These include:

  • eating a healthy, balanced diet
  • exercising regularly

This may help you lose any excess weight and keep it off, and will in turn help to improve your fertility and lower your testosterone levels. For tips and advice on how to eat healthily and exercise, see Related information below.

If you have more hair than usual, you could try hair removal techniques, such as hair removing creams, waxing, electrolysis or laser hair removal. Or you could give bleaching products a go.


A number of medicines can help to treat the different symptoms of polycystic ovary syndrome (PCOS).

  • Over-the-counter treatments that contain benzoyl peroxide (eg PanOxyl) can help to reduce acne. If these don't help, speak to your doctor. They may prescribe you some antibiotic creams.
  • Oral contraceptives can stop your ovaries from producing too much testosterone. This can help to improve acne and reduce hair growth.
  • A medicine called Metformin can improve your sensitivity to insulin, and can reduce your level of testosterone. As your level of testosterone drops, your fertility may improve and your ovaries may start releasing eggs.
  • If oral contraceptives aren’t suitable for you, or don’t work for you, your doctor may prescribe you eflornithine (Vaniqa) cream to reduce extra hair growth.
  • Fertility medicines, including clomifene citrate, can stimulate your ovaries to release eggs. Or you might want to consider assisted reproduction techniques, such as IVF (in vitro fertilisation). See Related information to learn more about fertility treatments.

Always read the patient information leaflet that comes with your medicine. If you have any questions, ask your pharmacist or doctor for advice.


If medicines don’t work for you, your doctor may suggest you have surgery to ease your symptoms and improve your fertility.

If you’re trying for a baby, one option is a procedure called laparoscopic ovarian drilling. This is a type of keyhole procedure that destroys the tissue on your ovaries that produces testosterone. As levels of testosterone fall, your polycystic ovary syndrome (PCOS) symptoms may improve and your ovaries may start to release eggs again.

Causes of polycystic ovary syndrome

At the moment, doctors don’t understand what causes polycystic ovary syndrome (PCOS). It’s likely that many things are involved, such as those below.

  • PCOS may run in families. You may have more risk of developing PCOS if a close family member, such as your mother or sister, has the condition.
  • Having high levels of certain hormones may cause PCOS. It’s thought that you may be less sensitive to insulin, the hormone that controls your blood sugar level. This means you need more insulin in your blood than usual to keep your blood sugar at a healthy level. The extra insulin may cause your ovaries to make too much testosterone, which can stop your ovaries from releasing an egg each month.

Complications of polycystic ovary syndrome

If you have polycystic ovary syndrome (PCOS), you may have a higher risk of developing:

Frequently asked questions

  • Ovarian hyperstimulation syndrome (OHSS) is a condition that develops if your ovaries overreact to medicines that stimulate the development of eggs in your ovaries.

    If you have polycystic ovary syndrome (PCOS), you’re more likely to develop OHSS if you’re having fertility treatment. You can also get OHSS after having reproductive techniques to help you have a baby, such as in vitro fertilisation (IVF).

    OHSS causes your ovaries to become larger than usual and symptoms include:

    • swelling or bloating in your abdomen (tummy)
    • tummy pain
    • feeling sick or vomiting
    • shortness of breath

    See your doctor if you have any of these symptoms and are having fertility treatment. If you have severe OHSS, you might need to go to hospital for treatment.

    You can still get pregnant if you have OHSS and have a normal pregnancy. But depending on your condition, your doctor might want to see you more regularly.

  • You're more likely to have complications during your pregnancy if you have PCOS.

    If you have PCOS, you’re more likely to develop diabetes during your pregnancy (gestational diabetes). You’ll be offered a test for this early on in your pregnancy. If you do get diabetes, your GP or midwife will refer you to a specialist clinic. Gestational diabetes usually goes away once your baby is born, but you might be more likely to develop type 2 diabetes later in life.

    You’re also more at risk of giving birth early and developing high blood pressure during your pregnancy. It’s possible you could develop a condition called pre-eclampsia, in which your blood pressure becomes dangerously high. Your obstetrician (doctor who specialises in pregnancy and childbirth) or midwife will regularly measure your blood pressure to check for this.

  • If you're overweight, losing weight often helps to improve the symptoms of PCOS.

    If you have PCOS, you may be less sensitive to insulin, the hormone that controls your blood sugar level. This means you need more insulin in your blood than usual to keep your blood sugar at a healthy level. The extra insulin may cause your ovaries to make too much testosterone, which can stop ovulation.

    Being overweight can make your symptoms worse. Exercising and eating healthily may help you to lose weight and become more sensitive to insulin. Here are some of the benefits.

    • If your periods are irregular, losing weight might make them more regular. Your chance of becoming pregnant may also improve.
    • Exercising regularly may also reduce your risk of type 2 diabetes and heart disease.
    • If you have acne, over time this may improve, and if you have excess hair, this may improve too.

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Related information

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    • Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press., accessed 29 February 2016
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    • Polycystic ovarian syndrome. Medscape., published 15 November 2015
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    • Ovarian hyperstimulation syndrome. Medscape., published 28 February 2015
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  • Reviewed by Rachael Mayfield-Blake, Freelance Health Editor, Bupa Health Content Team, March 2016
    Expert reviewer Dr Robin Crawford, Consultant Gynaecologist
    Next review due March 2019

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