Quick answer

What is polycystic ovary syndrome (pcos)?

PCOS is a common condition affecting how the ovaries work, causing irregular periods, excess androgen hormones and polycystic ovaries on scan. Symptoms include irregular cycles, acne, excess hair growth and weight gain. It cannot be cured but symptoms are manageable with lifestyle changes, contraception and other treatments.

What is PCOS?

Polycystic ovary syndrome (PCOS) is a common hormonal condition affecting how the ovaries work. Despite the name, the ovaries do not contain true cysts — they may show many small follicles on ultrasound that have not developed normally. PCOS affects roughly one in ten women in the UK and is a leading cause of irregular periods and fertility difficulties — though many women with PCOS conceive without problems.

Symptoms

PCOS symptoms vary. You may have some or many of the following:

Menstrual:

  • irregular periods — cycles longer than 35 days or fewer than 9 periods a year
  • absent periods
  • sometimes heavy bleeding when periods do occur

Androgen-related:

  • excess hair growth on the face, chest, back or buttocks (hirsutism)
  • acne and oily skin
  • thinning hair on the scalp (male-pattern hair loss)

Metabolic:

  • weight gain, especially around the waist
  • difficulty losing weight
  • darkened skin patches (acanthosis nigricans) in skin creases

Fertility:

  • difficulty getting pregnant due to irregular or absent ovulation

How PCOS is diagnosed

Diagnosis requires two of three features (Rotterdam criteria):

  1. Irregular periods or lack of ovulation
  2. Signs of raised androgen hormones — blood test or physical signs (excess hair, acne)
  3. Polycystic ovaries on ultrasound — 12 or more follicles on one ovary

A GP also rules out other conditions — thyroid problems, high prolactin, and non-classical congenital adrenal hyperplasia can cause similar symptoms.

What causes PCOS?

The exact cause is not fully understood. Key factors include:

  • Insulin resistance — higher insulin levels stimulate the ovaries to produce more androgens
  • Hormonal imbalance — raised luteinising hormone (LH) and androgens relative to oestrogen
  • Genetics — PCOS runs in families

Managing PCOS

There is no cure, but symptoms respond well to treatment:

Lifestyle — even 5–10% weight loss if overweight significantly improves periods, fertility, and insulin resistance. Regular exercise and a balanced diet help regardless of weight.

Contraception — the combined pill regulates periods and reduces androgen effects on skin and hair.

Metformin — improves insulin sensitivity; may help with weight, cycles and fertility.

Fertility treatment — clomifene or letrozole stimulate ovulation if trying to conceive.

Excess hair and acne — cosmetic treatments, anti-androgen medicines (co-cyprindiol, spironolactone), or specialist referral.

Long-term health

PCOS increases risk of type 2 diabetes, high cholesterol, high blood pressure, and endometrial problems from long gaps between periods. Regular health checks, weight management, and treating insulin resistance reduce these risks.

PCOS and mental health

PCOS is linked to higher rates of anxiety and depression — partly from hormonal effects and partly from the impact of symptoms on self-esteem. Mental health support is part of holistic care.

When to see a GP

See a GP if you have irregular periods, fertility concerns, or androgen symptoms. Early diagnosis helps manage long-term health and plan fertility if desired.

You do not need every symptom to warrant assessment — even irregular cycles alone are worth investigating.

Common questions

What are the main symptoms of PCOS?
Irregular or absent periods, excess hair growth on the face, chest or back (hirsutism), acne, oily skin, weight gain especially around the waist, thinning hair on the head, and difficulty getting pregnant. Not everyone has all symptoms — they vary widely.
How is PCOS diagnosed?
A GP looks for two of three features — irregular ovulation or periods, signs of raised androgen hormones (blood test or physical signs like excess hair), and polycystic ovaries on ultrasound. Other causes must be ruled out first.
Does PCOS cause infertility?
PCOS is a common cause of irregular ovulation, which can make conceiving harder. Many women with PCOS conceive naturally or with treatments such as clomifene. Weight loss if overweight significantly improves ovulation rates.
Can PCOS be cured?
There is no cure, but symptoms are very manageable. Lifestyle changes, hormonal contraception for cycle regulation, anti-androgen medicines for excess hair, and metformin for insulin resistance all help. Treatment is tailored to your priorities — whether that is fertility, skin, or cycle control.
Is PCOS linked to diabetes?
Yes. PCOS is associated with insulin resistance and higher risk of type 2 diabetes and high cholesterol. Regular monitoring of blood sugar and cholesterol, maintaining a healthy weight, and exercising reduce long-term risks.

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