PCOS Phenotypes (Rotterdam A through D)

By RRM Academy Reviewed by Dr. Naomi Whittaker, MD, Board-Certified OBGYN, MIGS, NFPMC, FCI Updated May 7, 2026

PCOS is diagnosed when two of three Rotterdam criteria are met: ovulatory dysfunction, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology on ultrasound. This produces four distinct phenotypes, each with a different metabolic and hormonal profile:

• Phenotype A (Full/Classic): All three features present. The most pronounced metabolic dysfunction and highest insulin resistance. This is the phenotype most likely to require aggressive metabolic intervention.
• Phenotype B: Ovulatory dysfunction plus hyperandrogenism, no polycystic morphology. Metabolic profile closely resembles Phenotype A.
• Phenotype C (Ovulatory): Hyperandrogenism plus polycystic morphology, with regular ovulation preserved. Milder metabolic impact than A or B.
• Phenotype D (Non-hyperandrogenic): Ovulatory dysfunction plus polycystic morphology, no hyperandrogenism. The least metabolically severe phenotype.

Phenotyping matters for treatment. Phenotypes A and B typically need insulin sensitization and metabolic correction before ovulation returns reliably. Phenotype C may respond to targeted hormonal support. Phenotype D often responds to ovulation induction without the full metabolic workup. Flying blind on phenotype means treating every PCOS presentation the same way, and that is how patients cycle through protocols for years without resolution.³⁹

This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.