PCOS Symptoms in Women: Signs, Causes and When to Get Checked

PCOS — polycystic ovary syndrome — is a hormonal condition that affects how the ovaries work. It can cause irregular periods, excess hair, acne, weight gain and difficulty getting pregnant. It affects an estimated 10–13% of women of reproductive age, yet up to 70% do not know they have it. There is no cure, but symptoms can be managed.

What is PCOS?

PCOS is a hormonal (endocrine) and metabolic condition. In PCOS, the ovaries produce unusually high levels of androgens — hormones often called “male” hormones, chiefly testosterone — ovulation becomes irregular or stops, and the ovaries may become enlarged and contain many small fluid-filled sacs (follicles) that surround immature eggs and usually fail to release an egg. The NHS explains that despite the name, you do not actually have cysts if you have PCOS: the features seen on scan are immature follicles, not true cysts.

In May 2026 the condition was officially renamed polyendocrine metabolic ovarian syndrome (PMOS), after a global consensus process, because the old name was misleading and did not reflect that it is a whole-body metabolic condition, not just an ovary problem. The NHS, Mayo Clinic and the UK charity Verity now use PMOS, but most people still search for PCOS, so this article uses PCOS and notes the new name.

Symptoms usually start in the late teens or early 20s, often at puberty, and continue until the menopause; after the menopause some symptoms stop or change. It is a chronic condition that persists beyond the reproductive years, not just a fertility or period problem, according to the World Health Organization (WHO).

How common is PCOS?

PCOS is very common, but estimates vary because they depend on the diagnostic criteria used and the population studied. The WHO estimates that PCOS affects 10–13% of women of reproductive age worldwide, and that up to 70% of women with PCOS worldwide do not know they have it. The UK charity Verity puts the UK figure at 1 in 8 women, while NHS Wales estimates about 1 in 5 women in the UK — and notes that more than half of these women have no symptoms at all. The range reflects different ways of counting, not disagreement about whether it is common: it is one of the most common hormonal conditions affecting women.

Symptoms of PCOS

Symptoms vary considerably from person to person, can change over time, and range from mild to severe. Some women have only one or two symptoms; others have several. The main symptoms are:

• Irregular, infrequent or absent periods. Periods may be fewer than eight a year, more than 35 days apart, very heavy, lasting many days, or stop altogether. This is the hallmark symptom, because it signals that ovulation is not happening regularly.
• Difficulty getting pregnant. Because ovulation is irregular or does not happen, PCOS is one of the most common causes of female infertility and the most common cause of anovulation (not ovulating) globally. Many women first discover they have PCOS when they try to conceive.
• Excess hair growth (hirsutism). Extra hair on the face, chest, back or buttocks, caused by high androgen levels.
• Oily skin or acne. Androgens stimulate oil production in the skin.
• Thinning hair or hair loss from the head. Female-pattern hair loss, usually on the top of the head.
• Weight gain or difficulty losing weight, especially around the waist. Symptoms are usually more serious in people with obesity, according to the Mayo Clinic.
• Feeling very tired, and thick, dark patches of skin on the neck or armpits (acanthosis nigricans), a sign of insulin resistance.
• Low mood, depression or anxiety. The NHS lists depression and anxiety among the main symptoms of PCOS, and the WHO notes that infertility, obesity and unwanted hair growth can carry social stigma, affecting confidence, relationships and quality of life.

What causes PCOS?

The exact cause of PCOS is unknown. What is known is that it involves abnormal hormone levels, and that it often runs in families — if your mother, sister or aunt has PCOS, your risk is higher, although no specific genes have been identified.

Insulin resistance is central to PCOS. Many women with PCOS are resistant to insulin, the hormone that controls blood sugar, so the body produces higher levels of it. High insulin drives the ovaries to produce too much testosterone, which interferes with follicle development and prevents normal ovulation. Insulin resistance can also lead to weight gain, which in turn makes the body produce even more insulin — a vicious circle, as NHS Wales explains.

Other hormone changes seen in PCOS include raised testosterone, raised luteinising hormone (LH), which stimulates ovulation but can have an abnormal effect on the ovaries if levels are too high, and low levels of sex hormone-binding globulin (SHBG), a protein that binds testosterone and reduces its effect. The NHS also notes that women may be more likely to have PCOS if a close relative has it or if they are from an Asian background.

How is PCOS diagnosed?

There is no single test that diagnoses PCOS. Diagnosis is usually made using the Rotterdam criteria: at least two of these three features, after other causes of the same symptoms have been ruled out.

1. Irregular or infrequent ovulation — irregular, infrequent or absent periods, indicating the ovaries do not regularly release eggs.
2. High androgen — signs such as excess hair growth, acne or hair loss, and/or blood tests showing high testosterone. A diagnosis can be made on signs alone, even if the blood test is normal.
3. Polycystic ovaries on ultrasound — many small follicles in enlarged ovaries. Polycystic ovaries alone do not mean PCOS, and you can have PCOS without polycystic ovaries.

To reach a diagnosis, a GP will ask about your symptoms and check your blood pressure. Tests can include blood tests to measure hormone levels and screen for diabetes or high cholesterol, and an ultrasound scan to look at the ovaries. The NHS notes that an ultrasound is only done if you are over 18. Depending on age and weight, annual checks of blood pressure and screening for diabetes may be offered after diagnosis. A GP may treat PCOS or refer you to a gynaecologist or an endocrinologist.

Long-term health risks

PCOS raises the risk of several longer-term health problems, which is why diagnosis and follow-up matter even if symptoms are mild:

• Type 2 diabetes — driven by insulin resistance, this is the best-evidenced long-term risk.
• High blood pressure, high cholesterol and cardiovascular disease, including heart disease and stroke.
• Fatty liver disease (non-alcoholic fatty liver disease).
• Sleep apnoea — interrupted breathing during sleep, particularly in women who are overweight.
• Endometrial (womb lining) cancer. Women who have had absent or very irregular periods — fewer than three or four periods a year — for many years have a higher-than-average risk, because the womb lining is exposed to oestrogen without regular shedding. The chance is still small, and it can be minimised with treatments that regulate periods, such as the contraceptive pill or an intrauterine system.
• Depression, anxiety and eating disorders, and a negative body image.
• Pregnancy complications, including gestational diabetes, high blood pressure in pregnancy, miscarriage and early birth.

Regular check-ups can reduce these risks. The NHS advises getting regular check-ups and talking to your doctor if you are worried.

How is PCOS managed?

There is no cure for PCOS, but symptoms can be managed. Treatment depends on your symptoms, current health and whether you are trying to get pregnant, and usually combines lifestyle changes and medicine.

Lifestyle changes

Healthy eating, regular exercise and losing weight if you are overweight are the first steps. NHS Wales notes that weight loss of just 5% can lead to a significant improvement in PCOS symptoms. Even without weight loss, healthy eating and physical activity matter, and exercise lowers blood sugar by improving how insulin works. The NHS also suggests talking therapy if symptoms are causing depression or anxiety.

Medicines

Medicines are chosen for the symptoms they target. The combined pill, the progestogen-only pill or an intrauterine system (IUS) can help with irregular periods and reduce androgen symptoms, while also protecting the womb lining. Metformin, a type 2 diabetes medicine, can help with tiredness and weight problems and encourage ovulation; it is not licensed for PCOS in the UK and is used “off-label” in certain circumstances. Spironolactone or eflornithine cream can help reduce unwanted hair growth, and skin creams or tablets can help acne. For fertility, clomifene is usually the first treatment to encourage ovulation; if it does not work, letrozole or metformin may be used, and a procedure called laparoscopic ovarian drilling may be suggested. With treatment, most women with PCOS are able to get pregnant. Talk to your doctor or pharmacist about which options suit you — do not start or stop any medicine on the basis of this article.

When to see a doctor

See a GP if you think you might have PCOS — for example, if your periods are irregular, infrequent or absent, if you are having trouble getting pregnant, or if you have signs of too much androgen, such as new facial or body hair growth, severe acne or male-pattern hair loss. Also see a GP if your symptoms are affecting your everyday life, work or relationships. Periods that are very infrequent or absent for a long time need checking, not ignoring, because of the higher womb-lining cancer risk. Low mood, depression or anxiety linked to symptoms also deserves support — the UK charity Verity offers information and peer support for anyone living with PCOS.

In an emergency call 911 (US), 999 (UK) or 112 (EU).