PCOS (Polycystic Ovary Syndrome): Symptoms, Diagnosis and Pregnancy

Periods that come every two months, or not at all. Spots that persist after adolescence, a few hairs on the chin, a belly that keeps rounding out despite your efforts. Taken one by one, these signs seem harmless. Together, they often point to PCOS, polycystic ovary syndrome, called takayyus al-mabayid (تكيس المبايض) in Arabic.

It is one of the most common hormonal disorders in young women. According to the WHO, it affects 10 to 13% of women of reproductive age, and up to 70% of them do not know it. Many find out when they start trying for a baby.

What is PCOS, and why is it changing its name?

PCOS is an imbalance that is both hormonal and metabolic. The ovaries produce slightly too much of the hormones known as male hormones (androgens), and insulin often works less well. As a result, the follicles that contain the eggs start to grow, then stop along the way, and ovulation becomes irregular.

The name is confusing. On an ultrasound, these small stalled follicles look like cysts, but they are not. That is one reason why an international consensus, published in The Lancet in May 2026, proposed a new name: polyendocrine metabolic ovarian syndrome (PMOS). The British NHS already uses it. A three-year transition is planned, and international guidelines will be updated by 2028.

The exact cause remains unknown. The NHS notes that having a relative with PCOS makes it more likely you will have it too.

What are the symptoms of PCOS?

Signs usually appear from puberty and vary a lot from one woman to another. The WHO and the NHS list:

• irregular cycles, very long ones, or no periods at all;
• difficulty getting pregnant;
• excess body hair (face, chest, belly) or, on the contrary, hair loss;
• acne or oily skin;
• weight gain, especially around the belly, and trouble losing kilos;
• patches of darker, thicker skin on the neck or under the arms, a sign of insulin resistance;
• tiredness, anxiety or low mood.

A woman may have only two or three of these signs. Conversely, irregular cycles can have other causes, which is why a proper diagnosis matters. To learn how to decode a cycle that behaves like a yo-yo, read our article on irregular cycles and ovulation.

How is PCOS diagnosed?

Diagnosis rests on the so-called Rotterdam criteria, confirmed by the 2026 consensus. In adults, you need at least two of the following three elements, once other possible causes have been ruled out:

In adolescents aged 10 to 19, the first two criteria are both required: an ultrasound alone is not enough, because many teenagers' ovaries look this way.

Once the diagnosis is made, the WHO advises looking for insulin resistance and assessing cardiovascular risk with a blood test. PCOS is not only a fertility question.

What does PCOS mean for your health?

PCOS needs long-term follow-up, even with no baby plans. The WHO lists several increased risks:

• metabolic: insulin resistance, type 2 diabetes, high cholesterol, fatty liver;
• cardiovascular: high blood pressure, sleep apnoea;
• gynaecological: thickening of the womb lining, even endometrial cancer if periods are very far apart for years;
• psychological: anxiety, depression, eating disorders, poor self-image.

These risks are not inevitable. Regular check-ups with your doctor allow early detection.

Which treatment for PCOS?

No treatment cures PCOS, but its symptoms can be managed very well. The choice is made with your doctor, depending on what bothers you most and whether you want a pregnancy.

Lifestyle first. The WHO recommends a healthy diet and regular physical activity for all women with PCOS, even if they do not lose weight. For women who are overweight, the NHS lists weight loss among the helpful measures, to be pursued without extreme dieting. Our article on what is proven about food and fertility separates serious advice from promises.

Prescribed treatments, never self-medicated, with the dose always set by the doctor:

• the combined pill, or a progestogen treatment, to regularise bleeding and protect the womb lining;
• treatments for acne or excess hair;
• metformin, a diabetes medicine, in certain situations;
• psychological support if your mood is low.

Be wary of supplements sold as "special PCOS" on social media: ask your doctor or pharmacist before taking any.

PCOS and wanting a baby: what to do?

Having PCOS does not mean being unable to have children. When ovulation is too rare, the gynaecologist can stimulate it with medicines, such as the clomifene mentioned by the NHS, with ultrasound monitoring. If that does not work, other options exist: a small keyhole operation on the ovaries, then insemination or IVF.

Any stimulation needs careful monitoring, as it carries a risk of multiple pregnancy and of ovarian hyperstimulation. Before starting, tests for both partners are still needed, as explained in our article on fertility tests for couples.

Pregnancy with PCOS: what follow-up?

Once pregnant, the pregnancy most often goes normally, but the WHO flags a higher risk of gestational diabetes and of high blood pressure in pregnancy. The NHS also lists PCOS among the factors that raise the risk of miscarriage.

In practice, mention your PCOS at the very first pregnancy appointment. The doctor can adapt diabetes screening and keep a close eye on your blood pressure. Everything about that screening is in our article on gestational diabetes.

Common myths about PCOS

• "I have cysts, they need to be removed." False: these are immature follicles, not cysts in the strict sense.
• "No cysts on the ultrasound, so no PCOS." False: the ultrasound is only one criterion out of three.
• "With PCOS, you cannot get pregnant." False: ovulation is irregular, not absent, and treatments exist.
• "It is a weight problem." Not only: slim women have PCOS, and the condition also affects skin, metabolism and mood.