Definition and significance of polycystic ovarian morphology: a task force report from the Androgen Excess and Polycystic Ovary Syndrome Society.
Level 5 - mechanism / opinion, no new human data
Expert task force consensus statement and narrative review
PubMed 24345633 · doi:10.1093/humupd/dmt061
What was done
An expert task force from the Androgen Excess and Polycystic Ovary Syndrome (AE-PCOS) Society reviewed peer-reviewed literature indexed in PubMed on polycystic ovarian morphology (PCOM). The panel evaluated transvaginal ultrasonography studies reporting antral follicle counts (AFC) or follicle number per ovary (FNPO) measuring 2–9 mm, 2–10 mm, or <10 mm in diameter in healthy women of reproductive age and women with PCOS to establish updated diagnostic thresholds.
What was found
Studies in women aged 18–35 years converged on an updated FNPO threshold of ≥25 follicles per ovary for defining PCOM, while supporting the maintenance of the ovarian volume threshold at ≥10 ml. Ovarian volume demonstrated lower diagnostic utility than FNPO, and specific metrics of ovarian stroma or blood flow provided no added diagnostic value. While serum anti-Müllerian hormone (AMH) performance matched or exceeded FNPO in some series, lack of assay standardization precluded setting a diagnostic threshold. Isolated PCOM in ovulatory women without androgen excess was not definitively linked to significant health consequences.
Why it matters
This statement updates the 2003 Rotterdam threshold of ≥12 follicles per ovary, which became obsolete due to higher-resolution ultrasound technology that detects more follicles in healthy women. It establishes new standardized diagnostic cutoffs to prevent overdiagnosis of PCOS in routine clinical practice and research.
Limits
The total number of studies and patients evaluated is not reported in the abstract. Recommendations for the ≥25 follicle cutoff depend strictly on modern high-resolution ultrasound transducers (≥8 MHz), requiring older equipment to default to ovarian volume. AMH could not be recommended due to inter-assay variability, and the clinical implications of isolated PCOM remain uncertain due to inconsistent historical definitions.
Cited by
- supports In PCOS, a polycystic ovary appearance on ultrasound is characterized by seeing 20 or more follicles arranged in a 'string of pearls' pattern.