What are the diagnostic criteria for Polycystic Ovary Syndrome (PCOS)?

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Last updated: March 25, 2025 • View editorial policy

From the Guidelines

The diagnostic criteria for Polycystic Ovary Syndrome (PCOS) should be based on the presence of at least two of three key features: oligo- or anovulation, clinical and/or biochemical signs of hyperandrogenism, and/or polycystic ovaries on ultrasound, as per the Rotterdam criteria 1. To diagnose PCOS, the following features should be considered:

  • Irregular or absent menstrual periods, indicating oligo-ovulation or anovulation
  • Clinical or biochemical signs of hyperandrogenism, such as hirsutism, acne, or male-pattern baldness, or elevated blood levels of androgens like testosterone
  • Polycystic ovaries on ultrasound, which can be diagnosed using transvaginal ultrasound showing at least 12 follicles measuring 2-9mm in diameter in either ovary, or increased ovarian volume exceeding 10mL However, it's essential to note that the use of ultrasound in PCOS diagnosis is controversial, and recent international PCOS guidelines recommend against using ultrasound in PCOS diagnosis within 8 years of menarche 1. Before diagnosing PCOS, other conditions with similar symptoms must be excluded, including thyroid disorders, hyperprolactinemia, congenital adrenal hyperplasia, androgen-secreting tumors, and Cushing's syndrome, typically through blood tests for thyroid function, prolactin levels, and other hormonal assessments 2. The most recent and highest quality study on this topic, published in 2024, emphasizes the need for a standardized definition of polycystic ovary morphology (PCOM) and highlights the controversy surrounding its use as a diagnostic criterion for PCOS 2.

From the Research

Diagnostic Criteria for Polycystic Ovary Syndrome (PCOS)

The diagnostic criteria for PCOS are based on the presence of at least two of the following three criteria:

  • Chronic anovulation
  • Hyperandrogenism (clinical or biological)
  • Polycystic ovary morphology (PCOM) 3, 4, 5, 6, 7

Key Features of PCOS Diagnosis

Some key features to consider when diagnosing PCOS include:

  • Menstrual irregularity, such as oligomenorrhea or anovulation 3, 4, 5, 6, 7
  • Hyperandrogenism, which can be clinical (e.g. hirsutism, acne) or biological (e.g. elevated androgen levels) 3, 4, 5, 6, 7
  • Polycystic ovary morphology on ultrasound, which is characterized by the presence of at least 25 small follicles (2-9 mm) in the whole ovary 3
  • Ovarian size, with a threshold of 10 mL between normal and increased ovary size 3

Diagnostic Challenges

Diagnosing PCOS can be challenging, particularly in adolescents, due to:

  • Variability in symptoms and presentation 3, 4, 5, 6, 7
  • Overlap with other conditions, such as congenital adrenal hyperplasia or androgen-producing tumors 4, 5
  • Limited sensitivity of testosterone assays in young girls 3

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.