Why it can take time

The signs of PCOS vary from person to person and change over time2. This is one of the reasons why many people with PCOS are not diagnosed3.

Age matters too: irregular cycles can be normal in the years after the first period, and again as menopause approaches. Clinicians therefore assess how regular the cycles are according to the time since the first period4.

In adults: three features examined

The 2023 international guideline makes the diagnosis when at least two of the following three features are present, once other causes have been ruled out5:

  • excess androgens, visible (hair growth, acne, hair loss) or measured with a blood test;
  • ovulation problems, which most often show up as irregular cycles;
  • the appearance of the ovaries on ultrasound, or, in adults only, an anti-Müllerian hormone (AMH) blood test instead of the ultrasound.

When irregular cycles and excess androgens are both present, neither an ultrasound nor an AMH test is needed6. The AMH test is never used as the only test, and it is not done in addition to an ultrasound, to avoid making the diagnosis wrongly7.

Ruling out other causes

Other conditions can produce similar signs, for example certain thyroid disorders or disorders of the hormone prolactin. Before concluding that it is PCOS, clinicians rule them out, depending on the situation, with tests such as TSH, prolactin, 17-OH progesterone or FSH levels8.

This is why a diagnosis can require several tests, and sometimes several appointments.

Contraception and tests

If you are taking the combined contraceptive pill, blood androgen tests are difficult to interpret reliably9. Your doctor may therefore ask you about your contraception before ordering certain tests.

Do not stop your contraception on your own to have tests: talk to the person who looks after you first, not least because pregnancy is still possible even with irregular cycles10.

In adolescents: different rules

Before adulthood, the benchmarks are not the same. Both features, excess androgens and ovulation problems, must be present; ultrasound and AMH are not recommended, because they are not very reliable at this age11.

Ultrasound and AMH are not used for this diagnosis until 8 years after the first period. A diagnosis can nevertheless be made earlier if irregular cycles and excess androgens are both present12.

An adolescent who has some signs without meeting these criteria can be considered “at increased risk”, with a reassessment later on13. Whether an assessment is worthwhile, and the right time for it, are discussed with the young person and with their parents or guardians14.

After the diagnosis

A PCOS diagnosis opens the way to follow-up care, not a verdict. Among other things, the guideline provides for15:

  • a blood sugar check at the time of diagnosis, then regularly depending on risk factors;
  • a cholesterol check at the time of diagnosis;
  • a blood pressure measurement every year.

It also provides for attention to your mood and to anxiety16, and to signs of sleep apnoea17. Information should be given to you respectfully, along with reliable resources to find out more18.

To prepare for this appointment, you can use our preparation kit and our list of questions.

Sources for this page

Each number leads to a neutral statement and to the documents that support it. We summarise these sources in our own words; the links open the original documents.

  1. 1

    Having some of these signs does not mean having PCOS: only a medical assessment can confirm the diagnosis.

    Established fact · checked on 18 October 2026

    Back to the text
  2. 2

    The signs and symptoms vary from one person to another, are not always present at the same time and can change over time.

    Established fact · checked on 18 October 2026

    Back to the text
  3. 3

    According to the WHO, up to 70% of the people affected are thought to be undiagnosed.

    Established fact · checked on 18 October 2026

    Global WHO estimate.

    Back to the text
  4. 4

    Whether cycles are irregular is assessed according to the time since the first period: irregular cycles can be normal at the beginning and at the end of the reproductive years.

    Recommendation · checked on 18 October 2026

    Back to the text
  5. 5

    In adults, the 2023 guideline makes the diagnosis when at least two of these three features are present, once other causes have been ruled out: clinical or biochemical signs of excess androgens; ovulation disorders; ovaries with a polycystic appearance on ultrasound, or a raised anti-Müllerian hormone (AMH) level instead of the ultrasound.

    Recommendation · checked on 18 October 2026

    Back to the text
  6. 6

    When irregular cycles and excess androgens are both present, neither an ultrasound nor an AMH test is needed for the diagnosis.

    Recommendation · checked on 18 October 2026

    Back to the text
  7. 7

    The AMH test should not be used as the only test for the diagnosis, and it is not done in addition to an ultrasound, in order to limit overdiagnosis.

    Recommendation · checked on 18 October 2026

    Back to the text
  8. 8

    Other possible causes of the same signs must be ruled out; depending on the situation, this involves tests such as TSH, prolactin, 17-OH progesterone or FSH levels.

    Recommendation · checked on 18 October 2026

    Back to the text
  9. 9

    While taking the combined contraceptive pill, blood androgen tests are difficult to interpret reliably.

    Recommendation · checked on 18 October 2026

    Back to the text
  10. 10

    A spontaneous pregnancy is still possible even with irregular ovulation: contraception is therefore useful when no pregnancy is planned.

    Established fact · checked on 18 October 2026

    Back to the text
  11. 11

    In adolescents, excess androgens and ovulation disorders must both be present; ultrasound and AMH are not recommended because they lack specificity at this age.

    Recommendation · checked on 18 October 2026

    Back to the text
  12. 12

    Ultrasound and AMH testing are not recommended for this diagnosis until 8 years after the first period; a diagnosis can nevertheless be made earlier if irregular cycles and excess androgens are both present.

    Recommendation · checked on 18 October 2026

    Some French sources count from puberty rather than from the first period (see research notes).

    Back to the text
  13. 13

    An adolescent who has some signs without meeting the criteria can be considered “at increased risk”, with reassessment advised no later than 8 years after the first period.

    Recommendation · checked on 18 October 2026

    Back to the text
  14. 14

    In adolescents, the value and the right timing of an assessment should be discussed with them and their parents or guardians, taking into account the difficulties specific to this age.

    Recommendation · checked on 18 October 2026

    Back to the text
  15. 15

    After diagnosis, the guideline provides in particular for a blood glucose check at diagnosis and then every 1 to 3 years depending on risk factors, a lipid profile at diagnosis, and a blood pressure measurement every year.

    Recommendation · checked on 18 October 2026

    Back to the text
  16. 16

    Depressive and anxiety symptoms are common; the guideline provides for screening for depression in adults and adolescents, and for anxiety in adults, at diagnosis and then according to the situation and life events.

    Recommendation · checked on 18 October 2026

    Back to the text
  17. 17

    Obstructive sleep apnoea is more common, independently of BMI; snoring with waking up unrefreshed, or sleepiness or tiredness during the day, are reasons to bring it up.

    Recommendation · checked on 18 October 2026

    Back to the text
  18. 18

    Information should be given respectfully and empathetically, and people with the condition should be directed to evidence-based resources rather than to misleading information.

    Recommendation · checked on 18 October 2026

    Back to the text