Polycystic ovary syndrome: Rotterdam criteria, phenotypes & life-stage management (International Guideline 2023)

A 29-year-old in your fertility clinic has had irregular cycles since menarche, an mFG score of 9, a BMI of 31, and an ovarian volume of 14 mL with 18 follicles per ovary. She is exhausted, anxious, and desperate to conceive. Your job is to confirm the diagnosis with the right test, exclude the mimics before labelling her, then walk the evidence-based ladder — lifestyle, letrozole, and an OHSS-aware IVF pathway if needed — while never losing sight of her cardiometabolic and psychological future. The Rotterdam framework and the 2023 International Guideline exist precisely to stop doctors calling the symptom a diagnosis and reaching for clomiphene first.[1][2]

Overview and definition

PCOS is the commonest endocrine disorder of reproductive-age women — prevalence around 8–13% using Rotterdam criteria, rising with ethnicity — and the leading cause of anovulatory infertility.[5] It is a syndrome, not a single disease: a cluster of ovulatory dysfunction, androgen excess, and a characteristic ovarian morphology, set against a backdrop of insulin resistance and chronic low-grade inflammation that does not disappear at menopause.[5][14]

The defining act of every consultation is the structured application of the Rotterdam criteria after exclusion of mimics. The syndrome has no cure; the phenotype shifts across the life course. The clinician's job is to treat the symptom in front of the woman today and to set up the surveillance that protects her tomorrow.[2][11]