Written by:

Dr Konstantinos Palaiologos


Dr Konstantinos Palaiologos (MD), is a specialty trainee in Obstetrics and Gynaecology in Yorkshire and the Humber. He has a passion for promoting the best health care for women and he is looking forward to developing his interest in fertility and benign gynaecology.  Dr Palaiologos is currently studying towards a PhD regarding a specialist fertility subject.

Polycystic ovary syndrome

In this article:

  • What is PCOS?
  • Symptoms of PCOS
  • What causes PCOS?
  • Testing for PCOS
  • What complications can PCOS lead to?
  • How does PCOS affect fertility?
  • How does PCOS affect pregnancy?
  • Management of PCOS
  • Main Points
  • References:

Polycystic ovary syndrome

What is PCOS?

Polycystic ovary syndrome (PCOS) is a hormonal imbalance that can have an impact on periods, fertility and aspects of your appearance. It is a common condition that affects 2 to 6 in every 100 women. In the longer-term it can also increase your risk of certain medical conditions including heart disease and diabetes.

Symptoms of PCOS

The word “syndrome” just refers to a group of symptoms, although the symptoms experienced will vary from woman to woman. Some women have only mild symptoms while others can be affected severely by a wide range of symptoms.

Potential symptoms include:

  • Menstrual disorders such as irregular periods or no periods at all
  • Increased facial or body hair, also known as hirsutism
  • Loss of hair on your head
  • Problems with weight such as obesity or being overweight (particularly around the waist), rapid increase in weight or difficulty losing weight
  • Oily skin, acne
  • Difficulty becoming pregnant

What causes PCOS?

The symptoms of PCOS are mainly related to abnormal hormone levels. Why some women get this condition is not yet fully known. It’s likely due to a combination of genetic and environmental factors. It often runs in families and the risk of developing PCOS may be increased if one of your relatives (mother, aunt, sister) is affected by the syndrome.

Hormones that are affected include:

  • Testosterone – Although you typically think of men when you think of testosterone, this hormone is also produced by women but in much smaller amounts by the ovaries. It may be increased in women with PCOS. It is responsible for symptoms of acne and hair gain or loss.
  • Insulin – This hormone controls the level of sugar (glucose) in the blood – when glucose goes up, so does insulin to help lower blood sugar. PCOS is associated with insulin resistance, which means that the body does not respond well to insulin. The sugar level stays higher and the body produces even more insulin to try and control it. Insulin resistance can lead to higher levels of testosterone and problems with all of FSH/LH function, follicle maturation and ovulation. It can also lead to weight gain.

Testing for PCOS

Some of the diagnosis is based purely on your symptoms, e.g. infrequent periods. In addition, the following tests are carried out:

  • Blood tests to check hormone levels
  • Pelvic ultrasound scan to assess the ovaries

PCOS is diagnosed according to the Rotterdam consensus criteria. To be diagnosed with PCOS you need to have any two of the following:

  1. Ovulatory dysfunction (irregular, infrequent periods or no periods at all)
  2. Hyperandrogenism (a blood test which shows increased testosterone, or symptoms of increased testosterone such as an increase in facial or body hair)
  3. Polycystic ovaries (enlarged ovaries containing multiple follicles on an ultrasound scan)

All of the symptoms of PCOS can also be caused by other less common conditions. These also need to be ruled out before you can be diagnosed with PCOS. See The menstrual cycle and hormones for examples of these tests.

What complications can PCOS lead to?

PCOS is associated with long-term health problems, including:

  • Type 2 diabetes – 40% of women with PCOS will develop type 2 diabetes or early features of this condition before the age of 40. This risk is increased if you are overweight
  • Hypertension – i.e. high blood pressure
  • Cardiovascular Disease – disease affecting blood vessels, including those supplying the heart and brain, putting women at increased risk of heart attack and stroke
  • Endometrial hyperplasia – if you do not have your period for more than 3-4 months but have a normal oestrogen level, the lining of your womb can become thickened. These cells are exposed to oestrogen for longer than they should be and can become overgrown and abnormal (hyperplasia). A small number of these women may go on to develop endometrial cancer (cancer of the lining of the womb) if this is left untreated.
  • Emotional wellbeing and challenges such as depression, anxiety, mood swings and low self-esteem.
  • Fatigue, sleepiness during the day, and snoring.

How does PCOS affect fertility?

Around 70% of women with PCOS may experience a delay or difficulty in becoming pregnant. This is because the infrequent or absent periods mean that ovulation (i.e. the release of an egg) is absent or infrequent. With fewer eggs, there are fewer chances in a year to get pregnant. The good news is with simple advice or treatment, most women with PCOS can get pregnant.

For most women ofchildbearing age, tiny fluid-filled cysts called follicles develop on the surface of the ovary every month. One of them will mature and produce an egg which is then released from the ovary. Female hormones play a vital role in this process. In PCOS a hormonal imbalance means that mature eggs are often prevented from developing and being released. Ovulation fails to occur and this may result in an irregular or absent menstrual cycle. The follicles continue to be present without releasing eggs, which results in multiple follicles around the surface of the ovaries. This causes the ovaries to appear larger than normal on an ultrasound scan.

It’s also important to consider that women with PCOS may also have other non-related issues that can cause reduced fertility, e.g. blocked fallopian tubes.

If you have PCOS and are interested in or actively trying to have a baby, have a look at this article on getting pregnant with PCOS.

How does PCOS affect pregnancy?

Women with PCOS have a higher risk of complications in their pregnancy. A recent study looking at 9 million pregnancies in the USA found that women with PCOS are two times more likely to develop gestational diabetes, 50% more likely to have raised blood pressure during pregnancy and at 30% increased risk of pre-eclampsia compared to women without PCOS. This was the case even when age, obesity, smoking and other risk factors were considered, though clearly having these additional risk factors further increases risk.

Management of PCOS

There is no specific “cure” for PCOS. Medical approaches aim to manage and reduce the symptoms or consequences of having PCOS.

Weight loss: this is really the first line treatment. Several studies show that even a modest weight loss of 5-10% of body weight can result in hormone levels normalising, the menstrual cycle regulating, better rates of ovulation and increased chances of getting pregnant.

Healthy lifestyle: To achieve weight loss and stick to it in the long-term requires a change in lifestyle. Exercise and a healthy diet are key. A healthy balanced diet includes fruit, vegetables, lean meat, fish, chicken and whole food (wholemeal bread, wholegrain cereals, brown rice and whole-wheat pasta) and cutting down the amount of sugar, salt, caffeine and alcohol. Experts advise regular exercise for 30 minutes at least three times a week.

Medication for menstrual irregularity: There are a variety of oral contraceptives (contraceptive pills) that can regulate the monthly cycle and protect the lining of the womb from overgrowth and hyperplasia. Some even have the added benefit of counteracting the negative symptoms that increased testosterone brings, e.g. acne. Alternatively, the intrauterine system (IUS or Mirena coil) can act to protect the lining of the womb and act as a contraceptive without needing to have a monthly period.

Management of hirsutism: Medications to control excessive hair growth include particular types of combined oral contraceptive tablets and other anti-androgen medications that block the effects of ‘male hormones’ (testosterone). You may also want to remove the unwanted hair by other methods of cosmetic therapy such as waxing, plucking, shaving, threading, creams or laser removal. 

Management of acne: There is a variety of prescription medication for moderate or severe acne such as topical retinoids; antibiotics in the form of gels, lotions or tablets; azelaic acid; and hormonal therapies (combined contraceptive pill, co-cyprindiol). 

Bariatric Surgery: For women with a BMI of 40 or above or of 30 and above with a high-risk obesity-related condition, weight loss surgery is an option.


Main Points

  • Polycystic ovary syndrome refers to a hormonal imbalance that can cause irregular periods and infertility; the condition may also have a long-term effect on your health.
  • PCOS is common, affecting 2 to 6 in every 100 women
  • PCOS is mainly related to abnormal testosterone and insulin levels.
  • Having polycystic ovaries (larger than the normal) does not necessarily mean that you have PCOS.
  • The symptoms vary from woman to woman. Some women have few mild symptoms while others can be affected severely by a wide range of symptoms. These include irregular periods, increase in facial hair, and thinning of hair on head.
  • Blood tests to check hormone levels or a pelvic ultrasound scan to assess ovaries can be used to diagnose PCOS. The condition is diagnosed according to the Rotterdam consensus criteria.
  • PCOS is associated with long-term health problems including diabetes and high blood pressure.
  • PCOS does not increase your chance of breast or ovarian cancer but it increases the risk of endometrial cancer.
  • Around 70% of women with PCOS may experience problems getting pregnant. The common cause of this is infrequent ovulation of anovulation.
  • During ovulation, tiny fluid-filled cysts (follicles) develop on the surface of the ovary. One of these will mature and release an egg. In women with PCOS, hormonal imbalance can prevent the egg from releasing (anovulation).
  • The management of infertility in women with PCOS consists of lifestyle changes, medical treatment and surgical intervention.
  • Many women with PCOS manage their symptoms without medical or surgical intervention.
  • Women with PCOS who are obese are advised to lose weight to improve their chances of conception.
  • Medication such as clomifene citrate or metformin or a combination of both which helps ovulation.
  • Other treatment options include laparoscopic ovarian drilling and the injection of gonadotrophins, which are hormones that stimulate the ovaries.
  • IVF is another path to explore if all other induction therapies are unsuccessful.
  • Medication alone has not been shown to be better than healthy lifestyle changes such as diet, exercise and weight loss if overweight for treating PCOS.


Information Leaflet: Polycystic Ovary Syndrome what it means for your long-term health, June 2015, RCOG
Fertility problems: assessment and treatment, NICE Clinical Guideline CG156, updated September 2017
NHS treatment for PCOS: https://www.nhs.uk/conditions/polycystic-ovary-syndrome-pcos/treatment/
Long term consequences of Polycystic Ovary Syndrome, Green-top Guideline No33, November 2014, RCOG
Clinical practice guidelines for Polycystic Ovary Syndrome, Australian NHMRC, ESHRE, ASRM July 2018
ASK PCOS Evidence based information for women with polycystic ovary syndrome, Monash University on behalf of NHMRC, Centre for Research Excellence in PCOS and the Australian PCOS Alliance 2018