PCOS Phenotypes (Rotterdam A through D)

By RRM Academy Reviewed by Dr. Naomi Whittaker, MD, Board-Certified OBGYN, MIGS, NFPMC, FCI Updated May 14, 2026

PCOS phenotypes are the four distinct clinical subtypes of polycystic ovary syndrome (PCOS), defined by the 2003 Rotterdam consensus based on which combination of three diagnostic criteria a patient presents. The three criteria are hyperandrogenism (clinical or biochemical), ovulatory dysfunction, and polycystic ovarian morphology (PCOM) on ultrasound. A PCOS diagnosis requires any two of the three. That two-of-three requirement produces four possible combinations, each designated a phenotype.¹²

Phenotype A carries all three features and represents the most pronounced metabolic and hormonal disruption, with the highest rates of insulin resistance and androgen excess. Phenotype B presents with hyperandrogenism and ovulatory dysfunction but lacks polycystic morphology; its metabolic risk profile closely mirrors Phenotype A. Phenotype C includes hyperandrogenism and polycystic morphology with ovulation preserved, producing a milder metabolic picture. Phenotype D presents with ovulatory dysfunction and polycystic morphology only, without hyperandrogenism, and carries the lowest metabolic risk of the four.²

Phenotype identification matters because treatment response varies substantially across subtypes. Phenotypes A and B tend to require insulin sensitization and metabolic correction before ovulatory function stabilizes. Phenotype C may respond to targeted hormonal support without a full metabolic workup. Phenotype D often responds to ovulation support with less aggressive intervention. Treating every PCOS presentation identically, without phenotyping, is how patients cycle through years of management without meaningful resolution.¹

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.