Polycystic Ovary Syndrome (PCOS): Diagnosis and Treatment

Polycystic ovary syndrome (PCOS) is one of the most common hormonal disorders in women of reproductive age. It affects periods, fertility, skin and hair, and long-term metabolic health. Despite its name, it is a whole-body endocrine and metabolic condition, not just a disease of the ovaries.

Diagnosis: the Rotterdam criteria

In adults, PCOS is diagnosed when two of these three are present, after other causes are excluded:

1. Irregular or absent ovulation: irregular, infrequent or absent periods.
2. Hyperandrogenism: clinical (hirsutism, acne, scalp hair loss) or biochemical (raised testosterone).
3. Polycystic ovarian morphology on ultrasound. The 2023 international guideline also allows a raised anti-Müllerian hormone (AMH) in adults instead of ultrasound.

In adolescents, both irregular cycles and hyperandrogenism are needed. Ultrasound and AMH are not recommended for diagnosis within 8 years of the first period, because polycystic-looking ovaries are normal at this age.

Conditions to exclude

• Thyroid disease (check TSH).
• High prolactin.
• Non-classic congenital adrenal hyperplasia (17-hydroxyprogesterone).
• Cushing's syndrome.
• Androgen-secreting tumours: suspect them with rapid-onset, severe virilisation or very high testosterone.
• Pregnancy.

Clinical features

• Menstrual: irregular or absent periods.
• Fertility: subfertility.
• Androgen effects:
  • hirsutism (excess hair on the face, chest and abdomen)
  • acne
  • male-pattern hair thinning
• Metabolic:
  • weight gain and difficulty losing weight
  • insulin resistance, sometimes with acanthosis nigricans (dark, velvety skin in the neck or armpits)
• Emotional: anxiety, depression and reduced quality of life.

Long-term health risks

• Type 2 diabetes and gestational diabetes.
• Dyslipidaemia and cardiovascular risk.
• Endometrial hyperplasia and cancer from long periods without a withdrawal bleed (unopposed oestrogen).
• Obstructive sleep apnoea.
• Fatty liver disease.
• Pregnancy complications.

Investigations

• Hormones:
  • total testosterone and sex hormone-binding globulin
  • TSH and prolactin
  • 17-hydroxyprogesterone
• Pelvic ultrasound in adults when needed.
• Metabolic screening:
  • oral glucose tolerance test or HbA1c
  • lipid profile
  • blood pressure
  • BMI
• Screening for depression and anxiety.

Management

Treatment is tailored to the woman's main concerns:

• Lifestyle: a healthy diet, regular exercise and weight management. Even 5–10% weight loss can restore ovulation and improve metabolic health.
• Irregular periods and endometrial protection: the combined oral contraceptive pill, or cyclical progestogens, or a levonorgestrel intrauterine system.
• Hirsutism and acne:
  • the combined pill
  • cosmetic methods (laser, electrolysis)
  • topical eflornithine
  • anti-androgens such as spironolactone, with effective contraception, because they are teratogenic
• Metabolic features: metformin may help, especially with a high BMI or impaired glucose tolerance.
• Infertility: letrozole is now first-line for ovulation induction (2023 international guideline). Clomifene, gonadotrophins, laparoscopic ovarian drilling and IVF are other options.
• Psychological support where needed.

Exam pearls

• Two out of three Rotterdam criteria, after excluding other causes.
• Do not use ultrasound to diagnose PCOS in adolescents.
• Women with infrequent periods need endometrial protection: aim for at least a withdrawal bleed every 3–4 months.

For more, see our Obstetrics & Gynaecology Companion (reproductive endocrinology chapter) and Exam Night Notes: Gynae & Obs.

Test yourself

5 exam-style single-best-answer questions. Choose your answer, then tap “Show answer”.

1. Rotterdam criteria require:

   1. Obesity plus acne
   2. All three criteria
   3. Ultrasound only
   4. Two of three, after excluding other causes
   5. High testosterone only
   Show answer

   Answer: D. Two of three, after excluding other causes
   Two of: ovulatory dysfunction, hyperandrogenism, polycystic ovarian morphology (or raised AMH in adults).

2. Why is ultrasound not used to diagnose PCOS in adolescents?

   1. Polycystic-appearing ovaries are normal within 8 years of menarche
   2. Hormones are not measurable
   3. It causes harm
   4. It is expensive
   5. It is always normal
   Show answer

   Answer: A. Polycystic-appearing ovaries are normal within 8 years of menarche
   Multifollicular ovaries are common in adolescence.

3. First-line drug for ovulation induction in PCOS (2023 guideline):

   1. Metformin alone
   2. Combined pill
   3. Letrozole
   4. Spironolactone
   5. Clomifene
   Show answer

   Answer: C. Letrozole
   Letrozole gives higher live birth rates than clomifene in PCOS.

4. Long periods without a withdrawal bleed increase the risk of:

   1. Fibroids
   2. Endometrial hyperplasia and cancer
   3. Cervical cancer
   4. Breast abscess
   5. Ovarian torsion
   Show answer

   Answer: B. Endometrial hyperplasia and cancer
   Unopposed oestrogen stimulates the endometrium; protect with progestogens or the pill.

5. Velvety dark skin in the neck of a woman with PCOS suggests:

   1. Vitiligo
   2. Eczema
   3. Psoriasis
   4. Melanoma
   5. Acanthosis nigricans from insulin resistance
   Show answer

   Answer: E. Acanthosis nigricans from insulin resistance
   Acanthosis nigricans is a sign of insulin resistance.

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Disclaimer

For education and exam preparation only. This is not medical advice and must not be used to diagnose or treat patients. Always follow current clinical guidelines and the advice of qualified senior colleagues.