Polycystic Ovary Syndrome (PCOS)

❍ At a glance

• PCOS affects approximately 8-13% of reproductive-age women. Most are undiagnosed. Consider it when a woman presents with irregular periods, acne, hirsutism, or difficulty conceiving - it is commonly missed.
• Rotterdam criteria: 2 of 3 features required - oligo/anovulation, clinical or biochemical hyperandrogenism, polycystic ovarian morphology on ultrasound. Exclude other causes first (thyroid, prolactin, late-onset CAH).
• Total testosterone is often normal in PCOS - use free androgen index or free testosterone. Polycystic ovarian morphology alone on ultrasound is not a diagnosis (present in 20-25% of women with regular cycles).
• Lifestyle (weight loss 5-10% in overweight women) is the most effective intervention across all PCOS domains. Frame it carefully - PCOS makes weight management physiologically harder.
• Annual metabolic review: HbA1c or fasting glucose, lipids, BP, BMI. PCOS carries a 4-fold increased risk of type 2 diabetes. Endometrial protection is a long-term concern in anovulatory cycles.

❍ Diagnosis: Rotterdam criteria and what to exclude

The Rotterdam criteria (2003) require two of three features:

• Oligo- or anovulation: irregular or absent periods, typically fewer than 9 cycles per year
• Clinical or biochemical hyperandrogenism: hirsutism (terminal hair in a male pattern - upper lip, chin, chest, linea alba, inner thighs), acne (especially adult-onset or persistent), female-pattern hair loss, or elevated free androgen index
• Polycystic ovarian morphology on ultrasound: 12 or more follicles per ovary measuring 2-9 mm, or ovarian volume over 10 mL

Important caveats: total testosterone is often within normal limits in PCOS - free androgen index is more sensitive. Polycystic ovarian morphology is present in approximately 20-25% of women with regular cycles; ultrasound findings alone do not make a diagnosis. In adolescents, polycystic morphology is common in the years following menarche, so diagnosis should rest on oligo-anovulation and clinical hyperandrogenism rather than imaging.

Before confirming PCOS, exclude: TSH (hypothyroidism causes irregular cycles and may coexist), prolactin (hyperprolactinaemia), 17-hydroxyprogesterone (late-onset congenital adrenal hyperplasia - particularly in women with significant hirsutism or family history), and dexamethasone suppression test if clinical features of cortisol excess are present. These diagnoses require different management.

❍ Metabolic assessment

Once PCOS is confirmed, assess metabolic risk comprehensively. Insulin resistance is present in 50-70% of women with PCOS and drives most of the long-term disease burden.

• Fasting glucose or HbA1c - women with PCOS have approximately a 4-fold increased risk of type 2 diabetes²
• Fasting lipid profile - dyslipidaemia is common
• Blood pressure
• BMI and waist circumference

Cardiovascular disease, non-alcoholic fatty liver disease, and obstructive sleep apnoea are all more prevalent in PCOS, independently of BMI. The metabolic workup is not optional - it shapes the urgency and intensity of management.

❍ Management by presenting concern

Lifestyle: Weight loss of 5-10% in women with overweight or obesity improves insulin resistance, restores ovulation, reduces androgen levels, and improves metabolic risk profile. It is the most effective single intervention across all PCOS domains. Frame it carefully - PCOS makes weight management physiologically harder due to insulin resistance and androgen effects on adipogenesis. This is not a willpower problem. Exercise has independent benefits on insulin sensitivity regardless of weight change.

Menstrual regulation and endometrial protection: The COCP is first-line for menstrual regulation and hyperandrogenism. Anti-androgenic progestogens (drospirenone, cyproterone acetate) provide additional benefit for acne and hirsutism. In women not wanting contraception, cyclical progestogen (medroxyprogesterone acetate or norethisterone for 10-14 days every 1-3 months) protects the endometrium in anovulatory cycles. Irregular periods from anovulation cause unopposed oestrogen exposure and endometrial hyperplasia risk - this is an underappreciated long-term concern.

Metabolic management: Metformin improves insulin sensitivity, lowers androgen levels, and reduces progression to type 2 diabetes. International PCOS guidelines support its use for metabolic and menstrual benefits.¹ It is not funded by PHARMAC specifically for PCOS (only for diabetes), but is inexpensive and widely accessible. Check current PHARMAC criteria at time of prescribing.

Subfertility: Letrozole (aromatase inhibitor) is now the preferred first-line ovulation induction agent, with higher live birth rates and lower multiple pregnancy risk than clomiphene citrate.³ Refer to a fertility specialist for ovulation induction - these medications require monitoring. Metformin as an adjunct improves outcomes in women with insulin resistance. IVF is reserved for those who do not respond to ovulation induction.

❍ Long-term monitoring and referral

Annual review for women with established PCOS should include: HbA1c or fasting glucose, lipid profile, blood pressure, BMI and waist circumference, and confirmation that the endometrium is being protected (either through regular cycles, contraceptive method, or cyclical progestogen). Pregnancy planning should be discussed - PCOS is associated with increased risk of gestational diabetes, pre-eclampsia, and preterm birth, and early obstetric review is appropriate.

Psychological wellbeing is a significant component of PCOS burden. Depression, anxiety, and disordered eating are all more prevalent. Screen with PHQ-9 and GAD-7 at diagnosis and when clinically indicated. Body image concerns are common, particularly in women with hirsutism and weight gain - acknowledge them directly.

Refer to endocrinology or gynaecology for: diagnostic uncertainty; severe or rapidly progressive hyperandrogenism (to exclude androgen-secreting tumour); subfertility requiring ovulation induction; and metabolic complexity warranting specialist input. Adolescents with suspected PCOS benefit from early specialist assessment to avoid normalising irregular cycles during the formative years after menarche.