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.
- Rapid progression, voice deepening, clitoromegaly, increased muscle bulk or severe biochemical androgen excess is not typical uncomplicated PCOS and needs urgent endocrine imaging pathways.
- Long gaps without endometrial shedding increase hyperplasia risk; offer reliable cycle control or progestogen exposure even when contraception is not required.
- Assess blood pressure, glucose status, lipids, sleep, weight trajectory, smoking and family cardiovascular risk without assuming that everyone with PCOS has obesity or insulin resistance.
- Treatment follows the person's goal: menstrual and endometrial protection, unwanted hair or acne, metabolic health, contraception, fertility or psychological wellbeing.
- Lifestyle support should be weight-neutral and stigma-aware where appropriate; clinically useful nutrition, movement and sleep interventions benefit health even without weight loss.
- NHS public terminology moved toward polyendocrine metabolic ovarian syndrome in 2026 while established guidance and this route retain PCOS; check final current NICE wording and do not treat a consultation draft as enacted guidance.
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.
Rapid onset over months, postmenopausal presentation, deep voice, clitoromegaly, marked muscle change or a severe laboratory elevation suggests ovarian or adrenal pathology rather than routine PCOS.
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.
- Apply the current diagnostic criteria; use ultrasound only if it contributes and explain that ovarian morphology alone is neither dangerous nor diagnostic.
- Document the phenotype, endometrial and metabolic risks, psychological needs and the individual's priorities, then agree a review and escalation plan.
Key medicines
Combined hormonal contraceptionUse a licensed low-risk preparation and schedule selected through the current UK contraceptive eligibility framework.Assess migraine with aura, thrombosis, smoking, blood pressure and other UKMEC factors. It alters androgen testing and is unsuitable when conception is desired.
Intermittent oral progestogenGive the locally recommended course often enough to provide endometrial protection when spontaneous bleeding is infrequent.Exclude pregnancy first and investigate persistent abnormal bleeding. The regimen does not treat hirsutism, guarantee ovulation or provide contraception unless the selected product is licensed for it.