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Polycystic ovary syndrome

Reproductive health

The commonest endocrine disorder of reproductive age: a diagnosis of two out of three, after other causes are excluded, with consequences that reach well beyond fertility.

Diagnosis (International guideline 2023, modified Rotterdam)

Polycystic ovaries on ultrasound with automated follicle counts and a 3D rendering: many small peripheral follicles, the string of pearls.
  • Two of three: oligo- or anovulation (cycles over 35 days or fewer than 8 a year), clinical or biochemical hyperandrogenism (hirsutism, acne, raised free testosterone or free androgen index), and polycystic ovarian morphology (or a raised AMH in adults as an alternative).
  • Exclude other causes: thyroid disease, hyperprolactinaemia, non-classical congenital adrenal hyperplasia (17-hydroxyprogesterone), Cushing's, an androgen-secreting tumour (rapid virilisation, very high testosterone).
  • In adolescents, ultrasound and AMH are not used; both irregular cycles (allowing for the years after menarche) and hyperandrogenism are required, otherwise the label is 'at risk' and reassessed.

Polycystic ovarian morphology

Transvaginal. An enlarged ovary.

Open in the Ultrasound Lab

Polycystic ovarian morphology

Transvaginal. Multiple small peripheral follicles.

Open in the Ultrasound Lab

What it means over a lifetime

  • Metabolic: insulin resistance, impaired glucose tolerance and type 2 diabetes, dyslipidaemia, obstructive sleep apnoea; screen with an OGTT or HbA1c and lipids, repeated every 1 to 3 years.
  • Endometrial: unopposed oestrogen from anovulation; induce a withdrawal bleed at least every 3 to 4 months or use a progestin-containing method to protect the endometrium.
  • Reproductive: anovulatory subfertility (letrozole is first line for ovulation induction), higher risks in pregnancy of gestational diabetes and hypertensive disorders.
  • Psychological: depression, anxiety, disordered eating and body image concerns are common and screened for.

Management

GoalOptions
Cycle regulation and endometrial protectionCombined hormonal contraception (first line); cyclical progestin; levonorgestrel IUD
Hirsutism and acneCombined hormonal contraception; spironolactone added after 6 months if needed (with contraception); mechanical hair removal; topical eflornithine
Metabolic healthLifestyle (any sustainable approach); metformin for metabolic features and in adolescents; GLP-1 agonists in selected cases
FertilityLetrozole first, then clomiphene, gonadotrophins or laparoscopic ovarian drilling; IVF

Metformin in PharmSpace

On the modelOvariesEndometrium

Frameworks and sources

  • International PCOS Network: International evidence-based guideline for the assessment and management of polycystic ovary syndrome (2023). Diagnosis by the modified Rotterdam approach; ultrasound morphology is never sufficient on its own, and is not used in adolescents.

Content reviewed 2026-09. Teaching material for students, not clinical decision support; check the current edition of the guideline your unit uses.