Rotterdam criteria for diagnosing PCOS

Author: Jessica Lloyd
Senior Vulvovaginal Specialist Naturopath | BHSc(N) | ISSVD, ISSWSH, BSSM, ATMS

Last reviewed: July 29, 2026

The Rotterdam criteria is an ever-evolving diagnostic guideline for the diagnosis of polycystic ovarian syndrome (PCOS).¹

Because PCOS is a syndrome – meaning, a collection of signs and symptoms often found together – no one set of criteria can be used exclusively for diagnosis. The original 1990 criteria were updated in 2004.

The Rotterdam criteria and diagnosis of PCOS requires two of these three manifestations:

Irregular or absent ovulation
Elevated levels of androgenic hormones
Enlarged ovaries or one ovary containing at least 12 follicles, measuring 2-9mm or have an increased volume of 10ml or more

Symptoms of PCOS that may assist diagnosis include:

Hyperandrogenism – testing free testosterone levels or free testosterone index
Polycystic ovaries
Menstrual irregularities
Signs of androgen excess
Obesity
Insulin resistance
Elevated blood luteinising hormone (LH) levels
Increased risk of type II diabetes, cardiovascular disease/events, and endometrial cancer

Symptoms of PCOS include

Hirsutism (male-type hair growth)
Menstrual irregularities
Acne

These criteria were updated by the European Society for Human Reproduction and Embryology (ESHRE), the American Society for Reproductive Medicine (ASRM), and cosponsored by the Rotterdam PCOS consensus workshop group in 2004, published in the January 2004 issue of Fertility and Sterility.^2,3

Testing should include metabolic syndrome testing for abdominal obesity (visceral fat), fat levels in the blood, high blood pressure, and glucose testing.

Those who have symptoms but don’t fit the clinical criteria may still have PCOS, however in a ‘mild’ form. Not everyone experiences PCOS the same way, with varying degrees of issues found.

Diagnosis of exclusion – things to rule out

Cushing’s syndrome
Androgen-secreting tumours
Congenital adrenal hyperplasia
Check follicle-stimulating hormone (FSH) levels and prolactin levels for thyroid conditions

Things to know about PCOS diagnosis

If the ovaries appear normal and there is no sign of hyperandrogenism, further testing is required. Just having polycystic ovaries is not enough, without other clinical signs, to provide a diagnosis of PCOS.

About half of those diagnosed with PCOS have insulin resistance, requiring glucose testing. LH/FSH ratios may be elevated in those with PCOS without recent ovulation, but researchers are not sure why.^4,5

Older studies didn’t find an increase in overall deaths, but PCOS does raise cardiometabolic risk, and a recent large cohort found a modest rise in mortality, driven by cardiovascular and cancer deaths.^6,7

Frequently asked questions

How is PCOS diagnosed?

PCOS is diagnosed using the Rotterdam criteria: you need two of three features – irregular or absent ovulation, signs of high androgens, and polycystic ovaries on ultrasound (at least 12 follicles measuring 2-9 mm, or an ovary volume of 10 ml or more). Other conditions have to be ruled out first.

Can you have PCOS with normal-looking ovaries?

Yes. Polycystic ovaries are only one of the three criteria, so you can be diagnosed on irregular ovulation and high androgens without them. Equally, simply having polycystic ovaries without other signs is not enough for a diagnosis.

What needs to be ruled out before diagnosing PCOS?

Conditions that mimic PCOS are excluded first, including Cushing’s syndrome, androgen-secreting tumours, congenital adrenal hyperplasia, and thyroid problems (checked with FSH and prolactin levels).

This article is general information and not a substitute for personalised medical advice. If you think you may have PCOS, please see an experienced practitioner.