Synopsis
Diagnose polycystic ovary syndrome only after excluding important mimics, then protect endometrial, metabolic, reproductive and psychological health through goals chosen with the individual.
- PCOS is a heterogeneous endocrine-metabolic syndrome, not an ultrasound description; polycystic ovarian morphology alone does not establish the diagnosis.
- In adults, diagnose after excluding mimics when two of ovulatory dysfunction, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology are present under the current guideline framework.
- In adolescents, normal pubertal irregularity and multifollicular ovaries create overdiagnosis; require persistent cycle disturbance plus hyperandrogenism and use specialist age-from-menarche criteria rather than adult shortcuts.
Key red flags
Very infrequent bleeding, prolonged amenorrhoea, persistent abnormal bleeding or a thickened endometrium increases concern for hyperplasia and requires a protection and investigation plan.
Investigation priorities
Exclude the commonest physiological cause of absent or irregular bleeding before endocrine interpretation.
Management branches
Persistent irregular cycles, hirsutism, acne or biochemical androgen excess in an adult.
- Clarify cycle pattern, pregnancy possibility, medications, hair progression, weight trajectory, sleep, mood, eating, fertility goals and red-flag virilisation; examine blood pressure, androgen signs and thyroid or Cushing features.
- Exclude pregnancy and common mimics with testosterone and SHBG, thyroid testing, prolactin and early-morning 17-hydroxyprogesterone, adding specialist tests only when indicated.
Key medicines
Combined hormonal contraceptionUse a licensed low-risk preparation and schedule selected through the current UK contraceptive eligibility framework.
Intermittent oral progestogenGive the locally recommended course often enough to provide endometrial protection when spontaneous bleeding is infrequent.