The Rotterdam Criteria Assessment
Two of three findings confirm PCOS — no single test suffices.
- 2 of 3: Criteria required (Rotterdam 2003 consensus)
- 8–13%: Global prevalence (reproductive-age women)
- ~2 yrs: Average diagnostic delay (symptom onset to diagnosis)
- ≥20: PCOM follicle threshold (per ovary, modern transducers)
The Rotterdam consensus
2003 ESHRE/ASRM meeting redefined PCOS diagnostic criteria.
Two of three criteria required — no single test confirms PCOS.
Oligo-ovulation criterion
Cycles longer than 35 days, or fewer than 8 per year.
Exclusion of mimics
Thyroid disease and hyperprolactinemia must be ruled out first.
Classic Severe PCOS — All Three Criteria
Oligo-ovulation, hyperandrogenism, and polycystic morphology co-occur here.
- ~50–65%: Share of PCOS cases (most common phenotype)
- ~70%: Insulin resistance (of phenotype A patients)
- Highest: Metabolic risk (among the four phenotypes)
- Elevated: Hirsutism score (Ferriman-Gallwey ≥8)
Full expression
All three Rotterdam criteria co-occur simultaneously.
Phenotype A carries the highest metabolic and cardiovascular risk.
Hormonal profile
Elevated LH:FSH ratio and hyperandrogenemia dominate.
Clinical management
Lifestyle intervention plus insulin sensitizers are first-line.
Classic Non-PCOM PCOS
Ovulatory dysfunction and androgen excess without polycystic ovaries.
- ~8–15%: Share of PCOS cases (less common phenotype)
- 0: Polycystic follicles (morphology criterion absent)
- Elevated: Androgen levels (clinical or biochemical)
- >35 days: Typical cycle length (oligomenorrhea)
Classic non-PCOM
Ovulatory dysfunction and androgen excess without polycystic ovaries.
Diagnostic nuance
Ultrasound can miss transient or resolved morphology.
Phenotype B still carries significant metabolic risk despite normal ultrasound.
Phenotype overlap
Some phenotype B cases evolve from phenotype A over time.
Ovulatory PCOS
Regular cycles mask underlying androgen and ultrasound findings.
- ~10–15%: Share of PCOS cases (ovulatory subtype)
- Regular: Ovulatory cycles (no oligo-ovulation)
- Moderate: Metabolic risk (milder than phenotype A)
- Favorable: Fertility outlook (relative to anovulatory types)
Ovulatory PCOS
Regular cycles mask underlying androgen excess.
Phenotype C is often missed because cycles appear normal.
Ultrasound findings
Polycystic morphology confirms diagnosis despite normal ovulation.
Fertility outlook
Generally better fertility prognosis than anovulatory phenotypes.
Mild, Non-Hyperandrogenic PCOS
Oligo-ovulation and morphology present, androgens stay normal.
- ~10–20%: Share of PCOS cases (mildest recognized phenotype)
- Normal: Androgen levels (non-hyperandrogenic)
- Lowest: Metabolic risk (among the four phenotypes)
- Ongoing: Diagnostic debate (some argue against true PCOS)
Mildest phenotype
Oligo-ovulation and morphology without hyperandrogenism.
Some experts debate whether phenotype D represents true PCOS.
Lower metabolic burden
Insulin resistance and cardiovascular risk are comparatively reduced.
Diagnostic caution
Other causes of oligo-ovulation must be excluded first.