What Is Polycystic Ovary Syndrome (PCOS)? Symptoms and Its New Name, PMOS

In brief:

• According to the WHO, PCOS affects 10–13% of women of reproductive age, and up to 70% of them are unaware of their condition.
• The new name, PMOS, describes the hormonal, metabolic and ovarian aspects of the condition. NHS pages now use this name (The Lancet, 2026; NHS).
• It is diagnosed, after other causes have been ruled out, when at least two of three criteria are present: signs of high androgens, irregular periods and polycystic ovaries on ultrasound (WHO).
• In PCOS the long-term risk of insulin resistance, type 2 diabetes and obesity increases (WHO).
• There is no cure, but lifestyle changes and treatments can ease the symptoms (NHS, WHO).

Why was PCOS renamed PMOS?

Under an international consensus published online in The Lancet on 12 May 2026, polycystic ovary syndrome was renamed polyendocrine metabolic ovarian syndrome (PMOS) (Teede et al., 2026). According to the consensus:

• The condition affects one in eight women.
• The old name gave a false impression: it implied diseased cysts in the ovaries and overshadowed the hormonal and metabolic aspects of the condition. This contributed to delayed diagnosis, fragmented care and stigma.
• For the new name, surveys were carried out among women with PCOS and health professionals from every region of the world; 14,360 people responded. 56 academic, clinical and patient organisations took part in the process.
• "Polyendocrine" refers to several hormone systems, "metabolic" to aspects of metabolism such as insulin and weight, and "ovarian" to the ovaries.
• A global implementation plan is under way for the transition period, education and alignment with disease classifications.

NHS pages updated in June 2026 use the new name and explain that "PMOS used to be called polycystic ovary syndrome (PCOS)". The name has changed; the condition is the same. If you were diagnosed with PCOS before, this does not mean a new diagnosis. It is normal for doctors and reports in Türkiye to keep using "PCOS" for a while; in this article we use both names together.

What are the symptoms of PCOS?

According to the NHS, symptoms usually start in the teenage years, before the age of 18, and continue until menopause. They can be mild or severe, or there may be no symptoms at all. Common symptoms:

• Irregular periods or long gaps between periods
• Excess facial and body hair (hirsutism) or hair loss
• Weight gain or difficulty losing weight
• Difficulty getting pregnant
• Mental health problems such as depression or anxiety
• Oily skin and acne
• Feeling very tired
• Thick, darker patches of skin on the neck or in the armpits (acanthosis nigricans)

The WHO notes that in some women periods may be heavy, long and painful rather than infrequent. We also explain darkening of the neck and armpits in Why Does the Intimate Area Darken?.

According to the NHS, most of these symptoms are common and can be caused by many other conditions. Having them does not mean you have PCOS, but it is important to get checked.

How is PCOS diagnosed?

According to the WHO, the diagnosis is made, after other causes of the symptoms have been ruled out, when at least two of these three criteria are present:

• Signs of high androgens (excess facial or body hair, hair loss, acne or oily skin) or a high testosterone level in the blood
• Irregular or absent periods
• Polycystic-looking ovaries on ultrasound

So some women with PCOS do not have a cystic appearance in their ovaries; cysts are not required for a diagnosis (WHO). The doctor also takes age into account: irregular periods can be normal in the first years after periods start and as menopause approaches (WHO).

According to the NHS, the tests are:

• blood tests to check hormone levels and insulin resistance;
• an ultrasound scan of the ovaries. The scan is only done in people over 18.

According to the WHO, women newly diagnosed are advised to have extra blood tests for insulin resistance and cardiovascular risk.

What is the link between PCOS and insulin resistance?

According to the NHS, the cause of PCOS is unknown, but it may be related to hormones such as insulin and testosterone not working properly. The WHO describes PCOS as a chronic metabolic condition that continues after the reproductive years; in the long term the risk of insulin resistance, type 2 diabetes and obesity increases.

The risk is higher in women with a family history of PCOS or type 2 diabetes (WHO). The NHS says the risk is higher in people with a close relative who has PCOS and in people of Asian background.

Which health risks does PCOS increase?

According to the NHS and the WHO, PCOS can increase the risk of:

• Type 2 diabetes and gestational diabetes
• High blood pressure, including high blood pressure in pregnancy
• Cardiovascular disease and high cholesterol
• Non-alcoholic fatty liver disease
• Sleep apnoea
• Thickening of the womb lining and womb cancer; infrequent periods can increase this risk (WHO)

According to the WHO, PCOS also affects quality of life. Anxiety, depression, eating disorders and body image problems may be more common. The NHS says regular check-ups can reduce these risks.

What can be done about PCOS?

According to the NHS and the WHO, there is no cure for PCOS; treatments and lifestyle changes can ease the symptoms. You and your doctor decide together what is right for you (WHO).

Lifestyle (NHS, WHO):

• Eating a balanced diet and exercising regularly. According to the WHO, this matters even if it does not lead to weight loss.
• Trying to lose weight if you are overweight
• Trying talking therapy if you have anxiety or depression
• Shaving, waxing, hair removal cream, electrolysis or laser for unwanted hair

Treatments a doctor may suggest (NHS):

• The contraceptive pill or a hormonal intrauterine system to regulate periods
• Medicines that help ovulation for those who want to get pregnant; if needed, a small laparoscopic procedure on the ovaries
• Medicines and creams for unwanted hair growth and acne
• A medicine also used in type 2 diabetes for tiredness and weight problems

According to the WHO, women with PCOS can be supported to get pregnant, but because the risk of complications in pregnancy is higher, they need closer monitoring.

When should you see a doctor?

According to the NHS:

• You think you may have PCOS
• Your symptoms are affecting your daily life, work or relationships

Also:

• Your periods are irregular or the gap between them is often longer than 35 days (NHS). We explain a one-off delay in Why Is My Period Late? and long-term irregularity in When and Why Do Irregular Periods Happen?.
• Your periods are irregular and you are struggling to get pregnant (NHS)

Frequently asked

Is PCOS the same as an ovarian cyst?

No. According to the WHO, cysts in the ovaries are not needed for a PCOS diagnosis; the ovaries of some women with PCOS look normal on ultrasound. According to the Lancet consensus, the old name was changed because it gave the impression of diseased cysts in the ovaries.

Can you get pregnant with PCOS?

Yes. According to the NHS, PCOS can make it harder to get pregnant because the ovaries may not release an egg every month. Medicines and procedures that help ovulation (NHS) and, if needed, assisted reproduction such as IVF (WHO) can be used. Closer monitoring is needed in pregnancy (WHO).

Does PCOS go away?

There is no cure (NHS, WHO). According to the NHS, some symptoms may disappear or change after menopause. The WHO stresses that the metabolic risks continue after the reproductive years; this is why regular check-ups matter.

Does PCOS cause weight gain?

The NHS lists weight gain or difficulty losing weight among the common symptoms of PCOS. If you are overweight, losing weight can help with symptoms (NHS). According to the WHO, a healthy diet and exercise matter even without weight loss.