Newly diagnosed with PCOS? Start by checking that it is actually PCOS.

PCOS is the commonest hormonal disorder in young women and one of the most loosely diagnosed. A great many women are told they have it on the strength of an ultrasound alone — and a good number of those do not have it at all.

The name is misleading

The "cysts" are not cysts. They are ordinary immature follicles, present in larger numbers than usual because ovulation is not happening regularly. Plenty of entirely healthy young women have ovaries that look polycystic on a scan, particularly in their late teens and early twenties. On its own, that appearance means very little.

What the diagnosis actually requires

Two of the following three, and — importantly — only after other causes have been excluded:

• irregular or absent ovulation, usually showing as infrequent, unpredictable or absent periods;
• androgen excess, either clinically (unwanted facial or body hair, persistent acne, scalp hair thinning) or on blood tests;
• polycystic ovarian morphology on ultrasound.

So a scan finding plus regular periods and clear skin does not amount to PCOS.

What must be ruled out first

This is the step most often skipped, and it matters because these conditions mimic PCOS and are treated quite differently: thyroid disease, raised prolactin, non-classical congenital adrenal hyperplasia, and less commonly Cushing's syndrome or an androgen-secreting tumour. Rapidly progressive hair growth or voice change in particular deserves prompt assessment rather than a PCOS label.

Treatment follows the complaint, not the diagnosis

There is no single treatment for PCOS, and this confuses many patients. What is offered depends on what is troubling you now.

Irregular periods. Regulating the cycle is not only about convenience — it protects the lining of the uterus from years of unopposed oestrogen. Combined hormonal contraception or cyclical progestogen are both reasonable.

Hair and skin. Treatment works but is slow: hair growth cycles mean three to six months before visible change, so stopping at two months and concluding it failed is the usual mistake.

Fertility. Most women with PCOS conceive, with or without help. This is worth saying plainly, because the diagnosis is often received as though it meant infertility.

Long-term metabolic risk. This is the part that persists after periods have been sorted out and the family is complete: an increased lifetime risk of prediabetes, type 2 diabetes, fatty liver and cardiovascular disease. Periodic screening is the reason PCOS deserves continued follow-up rather than a one-off prescription.

Weight, honestly

Not everyone with PCOS is overweight, and being told to lose weight when you are already slim is unhelpful. Where there is excess weight, though, even a modest reduction frequently restores ovulation and regularises cycles — it is among the most effective single measures available, which is why it comes up early.