Getting answers

How PMOS is diagnosed

No single test confirms PMOS. Knowing what clinicians are actually looking for makes the process far less opaque.

Written by the Lila team · Sources linked below · 2 min read · Updated

There is no single test for PMOS. That surprises people, and it's the main reason diagnosis so often drags on for years.

Instead, clinicians work from an international set of criteria, updated in 2023 and built on what were long known as the Rotterdam criteria.

The two-of-three rule

In adults, a diagnosis requires at least two of the following three features:

  • Raised androgens: either visible signs such as acne or excess hair growth, or elevated levels on a blood test
  • Ovulatory dysfunction: usually irregular or absent cycles
  • Polycystic ovarian morphology: the appearance of the ovaries on ultrasound, or, newly permitted in 2023, a raised anti-Müllerian hormone (AMH) blood level instead

Two details matter here. The 2023 update added AMH as an alternative to ultrasound in adults, which means a GP can often progress the diagnosis without a scan. And if you already have both irregular cycles and raised androgens, roughly 70% of cases, you need neither an ultrasound nor an AMH test. That combination is enough.

A normal ultrasound does not rule PMOS out. Many people are diagnosed without one.

Ruling other things out

Criteria alone aren't sufficient. Other conditions can produce the same picture, thyroid disorders and raised prolactin among them, and these must be excluded first. This is why blood tests usually come in a panel rather than one at a time.

If you're under 18

Adolescents are assessed differently. Both raised androgens and ovulatory dysfunction are required, and ultrasound and AMH are not recommended, because the normal changes of puberty overlap too closely with the criteria to be reliable.

What helps

Because diagnosis rests on cycle history and symptom patterns, your own record is genuinely diagnostic material, not just context. Cycle lengths across several months, when symptoms appear, and how they cluster give a clinician something concrete to assess. It's the single most useful thing you can bring.

Lila is a companion and a record, not a doctor. This article is general information, not advice about your situation. If any of this sounds familiar, please speak to a clinician.

Quick answers

How is PMOS diagnosed?

There is no single test. In adults, a diagnosis needs at least two of three features: raised androgens, ovulatory dysfunction (usually irregular or absent cycles), and polycystic ovarian morphology on ultrasound or a raised anti-Müllerian hormone (AMH) level. Other conditions, such as thyroid disorders and raised prolactin, must be ruled out first.

Can PMOS be diagnosed without an ultrasound?

Yes. The 2023 guideline allows an AMH blood test instead of ultrasound in adults, and if you already have both irregular cycles and raised androgens, you need neither an ultrasound nor an AMH test.

Does a normal ultrasound rule out PMOS?

No. A normal ultrasound does not rule PMOS out, and many people are diagnosed without one.

How is PMOS diagnosed in teenagers?

Under 18, both raised androgens and ovulatory dysfunction are required, and ultrasound and AMH testing are not recommended, because the normal changes of puberty overlap too closely with the criteria.

Sources