Four patterns of PCOS (A to D) based on which of the three Rotterdam features are present.
Why it matters for PCOS
A PCOS diagnosis uses three Rotterdam features: irregular ovulation, signs of high androgens (clinical or on blood tests), and polycystic ovaries on ultrasound. Depending on which features are present, PCOS is grouped into four phenotypes: phenotype A has all three, B has irregular ovulation plus high androgens, C has high androgens plus polycystic ovaries with normal ovulation, and D has irregular ovulation plus polycystic ovaries without high androgens.
Phenotypes help explain why symptoms differ from one woman to another, and they are sometimes linked to differences in metabolic risk. Your phenotype is determined by a doctor after reviewing your cycle history, androgen tests, and ultrasound together, and treatment is still guided by your individual symptoms rather than the phenotype label alone.
This glossary is education, not diagnosis. For your own situation, ask a doctor or pharmacist.