What it means

PCOS is a long-term condition in which the ovaries do not release eggs regularly and produce higher levels of androgens. It typically presents in adolescence and is one of the most common hormonal conditions affecting people of reproductive age.

It is diagnosed by pattern, not by a single test. Common criteria, used in combination, include:

  • Irregular or absent periods
  • Clinical signs of high androgens: acne, excess body or facial hair, thinning hair on the scalp
  • High androgen levels in blood tests
  • Polycystic ovaries on ultrasound — and importantly, having polycystic ovaries alone does not mean PCOS

What can vary

Possible explanations

Before settling on PCOS, a clinician excludes the alternatives, because they need different treatment:

  • Thyroid disease — can cause very similar period and weight changes.
  • Elevated prolactin — changes periods and often causes breast discharge.
  • Very low energy availability — from intensive training or low intake; causes absent periods.
  • Other causes of absent periods — including pregnancy, which is always excluded first.

This is also why a single blood test does not diagnose PCOS. The pattern across two or more features, over time, is what the diagnosis rests on.

  • Weight is not a diagnostic criterion. PCOS happens across all body sizes, and it is frequently missed in people who do not have “typical” features. Weight is one risk factor for metabolic complications, not a diagnostic feature.
  • Not everyone has all features. Some have irregular periods only; some have acne and hair growth but regular periods.
  • Symptoms often change with age, and diagnosis can be harder in teenagers, because irregular periods in the first years after the first period are common and acne is common too. Deliberately delaying diagnosis is recommended unless the symptoms are severe.
  • Ethnicity affects presentation and risk, and diagnostic criteria are being revised to account for this.

Why it matters beyond periods

Untreated, PCOS is associated with:

  • Low bone density, because periods are infrequent and oestrogen is low
  • Insulin resistance and increased risk of type 2 diabetes
  • Increased cardiovascular risk
  • Difficulty conceiving — though many people with PCOS conceive naturally, and it is treatable

What can be done

  • Cycle control: the combined contraceptive pill is often first-line; progestogen-only options and other hormonal treatments are alternatives.
  • Acne: standard acne treatments, sometimes including anti-androgens.
  • Hair growth: laser or electrolysis work; there are no creams that remove hair permanently.
  • Fertility: there are effective treatments, including ovulation induction.
  • Metabolic health: weight-neutral approaches focus on strength training, sleep and diet quality rather than restriction.
  • Bone health: worth protecting if periods stay infrequent for long.

Warning signs

  • Periods stopping for three months or more — worth assessing regardless of pregnancy plans, because of bone density.
  • Rapid development of acne or hirsutism alongside period changes.
  • Sudden severe pelvic pain with absent periods — urgent, to exclude ectopic pregnancy.
  • Symptoms of diabetes: extreme thirst, frequent urination, unexplained tiredness.

What to do next

Book an appointment and describe your pattern: cycle lengths, acne, hair growth, and any difficulty conceiving. Ask specifically whether PCOS is being considered and what tests would help.

If you have irregular periods, ask about protecting bone health. It is the most commonly missed part.

Self-care

There is no self-care that treats PCOS, but the following genuinely help with the metabolic side, regardless of weight:

  • Strength training has good evidence for insulin sensitivity.
  • Sleep.
  • Regular meals, and avoiding over-restriction, which can worsen cycles.
  • Reducing sugary drinks.
  • Tracking symptoms so you can see what helps.

Weight stigma is particularly harmful in PCOS, and any advice centred on weight alone should be treated with scepticism.

When to seek help

Routine: irregular periods worth investigating.

Prompt: three months without a period, or new severe acne with irregular cycles.

Emergency: sudden severe pelvic pain with absent periods.

How to talk about it

“My periods are every two or three months and I also get bad acne.”

“I’ve got irregular periods and increased hair growth. Should PCOS be considered?”

“I’m not trying to get pregnant but I’m worried about my bones.”

That last sentence is one of the most useful things a young person can raise, because it gets the bone health point on the record.

Sources

Public sources are linked so you can read the detail rather than take this site’s word for it. None of this has yet been reviewed by a qualified clinician — see how we handle medical review.

Keep reading

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References

Where this comes from

Linked so you can check it against a recognised public health source rather than take this site's word for it.

  1. Polycystic ovary syndrome — NHS NHS (opens in a new tab)
  2. PCOS — ACOG American College of Obstetricians and Gynecologists (opens in a new tab)

These are public sources from recognised health organisations, linked so you can read the detail rather than take this site's word for it. Reading them does not tell you whether any of it applies to you, and none of these articles has yet been reviewed by a qualified clinician. How we handle sourcing and review.