MedSearchGraphRAG
6 quiz questions available for this topicTake Quiz

Polycystic ovary syndrome

SNOMED: 237055002922 words•Updated 03/03/2026
💡

Exam Tips

  • For adults, remember diagnosis is clinical after exclusion: hyperandrogenism + ovulatory dysfunction (with or without ultrasound morphology depending on pathway).
  • In adolescents, avoid over-diagnosis: menstrual irregularity is common in year 1 post-menarche; persistent irregular cycles plus hyperandrogenism are more suggestive.
  • Acanthosis nigricans is a high-yield clue to insulin resistance and future diabetes risk in PCOS.
  • Chronic anovulation means unopposed estrogen: always think endometrial protection if infrequent bleeds.
  • If biochemical androgen testing is essential, combined oral contraception should be stopped for about 3 months before testing to improve interpretability.
  • In OSCE counselling, include fertility, cardiometabolic risk, mental health screening, and preconception optimization.

Definition

Polycystic ovary syndrome (PCOS) is a common, chronic, heterogeneous endocrine disorder of reproductive-age females, usually emerging around puberty. It is defined clinically by combinations of hyperandrogenism, ovulatory dysfunction (for example oligomenorrhoea or amenorrhoea), and/or polycystic ovarian morphology after exclusion of other causes of androgen excess and menstrual disturbance.

Pathophysiology

PCOS is multifactorial, with genetic susceptibility interacting with environmental factors (especially adiposity). A key mechanism is insulin resistance with compensatory hyperinsulinaemia, which lowers hepatic sex hormone-binding globulin (raising free testosterone) and stimulates ovarian theca-cell androgen production; altered LH pulsatility (raised LH relative to FSH in many patients) further promotes androgen excess. Follicular maturation arrests, causing chronic anovulation and irregular bleeding, while ongoing oestrogen exposure without regular progesterone withdrawal increases endometrial hyperplasia risk. Obesity amplifies insulin resistance and peripheral aromatization, worsening reproductive and metabolic features. Image reference for revision: use a standard HPO-axis/theca-granulosa steroidogenesis diagram from your endocrine notes.

Risk Factors

  • Family history of PCOS
  • Insulin resistance
  • Overweight or central obesity
  • History or signs of metabolic syndrome
  • Ethnicity-associated higher prevalence groups (for example Black and Middle Eastern populations in epidemiological studies)
  • Adolescent significant weight gain

Clinical Features

Symptoms

  • Infrequent periods (oligomenorrhoea)
  • Absent periods (amenorrhoea)
  • Subfertility or infertility due to anovulation
  • Acne (often persistent or severe)
  • Excess facial/body hair growth
  • Scalp hair thinning (female pattern hair loss)
  • Weight gain or difficulty losing weight
  • Psychological symptoms (low mood, anxiety, disordered eating features)
  • Sleep-disordered breathing symptoms (snoring, daytime somnolence)

Signs

  • Hirsutism on exam
  • Inflammatory acne
  • Female pattern alopecia
  • Central adiposity/raised BMI
  • Acanthosis nigricans indicating insulin resistance
  • Hypertension
  • Features of anovulatory bleeding pattern

Investigations

Urine or serum beta-hCG:Negative (to exclude pregnancy as a cause of amenorrhoea)
Total/free testosterone (or calculated free androgen index), SHBG:Biochemical hyperandrogenism and/or low SHBG; if on combined oral contraception, androgens may be suppressed and testing is unreliable
Serum prolactin:Usually normal in PCOS; raised level suggests hyperprolactinaemia
TSH:Usually normal in PCOS; abnormal result suggests thyroid dysfunction
17-hydroxyprogesterone (early morning, follicular phase if cycling):Normal in PCOS; elevated level suggests non-classic congenital adrenal hyperplasia
LH and FSH:LH may be elevated with increased LH: FSH ratio, but this is not required for diagnosis
HbA1c and/or oral glucose tolerance test (especially if high risk):May show impaired glucose tolerance or type 2 diabetes
Fasting lipid profile:May show dyslipidaemia (raised triglycerides, low HDL, raised LDL)
Pelvic ultrasound (adult diagnostic context):Polycystic ovarian morphology may be present; diagnosis in adults can be made from clinical/biochemical criteria without mandatory scan in many cases
Blood pressure, BMI, waist circumference:Cardiometabolic risk factors may be elevated

Management

Lifestyle Modifications

  • Structured weight-management support with realistic weight-loss targets if overweight (even modest loss can improve ovulation and metabolic markers)
  • Regular physical activity (aerobic plus resistance training) and dietary pattern change to reduce insulin resistance
  • Screen and address mood, anxiety, sleep quality, and eating disorder symptoms early
  • Smoking cessation and cardiovascular risk reduction
  • Preconception counselling: optimize weight, glycaemia, blood pressure, and folic acid use before conception

Pharmacological Treatment

Cycle control and endometrial protection

  • Combined oral contraceptive pill (for example ethinylestradiol 30 micrograms with levonorgestrel 150 micrograms, 1 tablet daily for 21 days in a 28-day cycle)
  • Intermittent progestogen withdrawal regimen if not using COC (for example medroxyprogesterone acetate 10 mg once daily for 5-10 days every 1-3 months)

Used to regulate bleeding and reduce endometrial hyperplasia risk in chronic anovulation. Check UKMEC contraindications to estrogen-containing contraception (for example migraine with aura, uncontrolled hypertension, current VTE, smoking age 35 or over, severe obesity with additional risk factors).

Insulin sensitizer (metabolic and ovulatory support)

  • Metformin immediate-release 500 mg once daily with food, titrating every 1-2 weeks to 500 mg three times daily (or 1 g twice daily modified-release) as tolerated

Common GI adverse effects; titrate gradually. Avoid/start cautiously in renal impairment and follow BNF renal safety advice; withhold during severe intercurrent illness or dehydration due to lactic acidosis risk.

Hirsutism/acne adjuncts

  • Eflornithine 11.5% cream, apply thin layer to affected facial areas twice daily (at least 8 hours apart)
  • Spironolactone 50-100 mg once daily (up to 200 mg/day in specialist practice, off-label for hirsutism)

Anti-androgens are teratogenic risk in male fetus: ensure reliable contraception and stop before conception attempts. Monitor potassium/renal function with spironolactone; avoid in significant renal impairment or hyperkalaemia.

Ovulation induction for infertility (specialist care)

  • Letrozole 2.5 mg once daily for 5 days early in cycle, may escalate to 5 mg then 7.5 mg in subsequent cycles if needed
  • Clomifene citrate 50 mg once daily for 5 days, titrating up to 150 mg/day if no ovulation
  • Gonadotrophins (FSH preparations) with ultrasound monitoring in fertility services

Letrozole is first-line ovulation induction in many UK pathways. Counsel regarding multiple pregnancy risk (higher with clomifene/gonadotrophins), ovarian hyperstimulation risk, and need for specialist monitoring.

Surgical / Interventional

  • Laparoscopic ovarian drilling for clomifene/letrozole-resistant anovulatory infertility in selected patients under specialist fertility services

Complications

  • Anovulatory infertility
  • Endometrial hyperplasia and increased endometrial cancer risk (from prolonged unopposed estrogen exposure)
  • Impaired glucose tolerance and type 2 diabetes mellitus
  • Dyslipidaemia and metabolic syndrome
  • Hypertension and increased long-term cardiovascular risk profile
  • Obstructive sleep apnoea/sleep-disordered breathing
  • Pregnancy complications (including gestational diabetes, hypertensive disorders, miscarriage, preterm birth, caesarean delivery)
  • Depression, anxiety, and eating disorders

Prognosis

PCOS is a long-term condition without a single curative therapy, but symptoms and risk can be substantially improved with sustained lifestyle and targeted medical treatment. Hyperandrogenic features often lessen with age and after menopause as ovarian activity declines, while metabolic and cardiovascular risk may persist and needs ongoing surveillance.

Sources & References

💊BNF Drug References(3)

✅NICE Guidelines(1)

📖Textbook References(20)

  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1840, 1841)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1224, 1225)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1221)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1840)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1303)[context]
  • David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1306, 1307)[context]
  • Emergencies in - Obstetrics and Gynaecology, Second Edition (Stergios K. Doumouchtsis, S. Arulkumaran) (Z-Library).pdf(pp. 294, 295)[context]
  • Emergencies in - Obstetrics and Gynaecology, Second Edition (Stergios K. Doumouchtsis, S. Arulkumaran) (Z-Library).pdf(pp. 295, 296)[context]
  • Emergencies in - Obstetrics and Gynaecology, Second Edition (Stergios K. Doumouchtsis, S. Arulkumaran) (Z-Library).pdf(pp. 18, 19)[context]
  • Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 974)[context]
  • Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 974)[context]
  • Guyton and Hall Textbook of Medical Physiology (John E. Hall, Michael E. Hall) (Z-Library).pdf(pp. 974)[context]
  • Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 91)[context]
  • Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 128)[context]
  • Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 127, 128)[context]
  • Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 674, 675)[context]
  • Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 673, 674)[context]
  • Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 90, 91)[context]
  • Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 422, 423)[context]
  • Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 309)[context]

Sources

Test Your Knowledge

6 quiz questions available for this topic

Start Quiz