PCOS (Polycystic Ovary Syndrome)

What is PCOS?

Polycystic ovary syndrome is a complex endocrine and metabolic condition characterised by a combination of hormonal imbalance, ovulatory dysfunction, and often metabolic disturbances. Despite its name, the “cysts” seen on ultrasound are not true cysts but small follicles that have failed to mature fully.

PCOS is not simply a reproductive condition. It has wide-ranging effects on metabolism, cardiovascular health, mental wellbeing, and quality of life, requiring a holistic approach to care.

Diagnosis

Diagnosis is based on the Rotterdam criteria, which require the presence of at least two of the following three features:

• Oligo-ovulation or anovulation — irregular, infrequent, or absent periods (cycles longer than 35 days or fewer than 8 cycles per year)
• Clinical or biochemical hyperandrogenism — signs of excess male hormones, such as acne, hirsutism (excessive hair growth on the face, chest, or back), or elevated androgen levels on blood tests
• Polycystic ovarian morphology — 12 or more follicles (2–9 mm) per ovary or an ovarian volume exceeding 10 mL on ultrasound

Other conditions that can mimic PCOS — thyroid disorders, congenital adrenal hyperplasia, Cushing’s syndrome, and prolactinoma — must be excluded before a diagnosis is confirmed.

The different phenotypes

PCOS is not a single condition but encompasses several distinct phenotypes, each with a different clinical profile and risk pattern:

• Phenotype A (classic) — hyperandrogenism + ovulatory dysfunction + polycystic ovaries. The most common and metabolically severe form
• Phenotype B — hyperandrogenism + ovulatory dysfunction, without polycystic ovaries on imaging
• Phenotype C (ovulatory PCOS) — hyperandrogenism + polycystic ovaries, with regular cycles. Often underdiagnosed because menstruation appears normal
• Phenotype D (non-hyperandrogenic) — ovulatory dysfunction + polycystic ovaries, without signs of excess androgens. The mildest metabolic profile

Identifying the phenotype helps tailor the treatment approach and determine which metabolic screening is most appropriate.

Metabolic assessment

PCOS is associated with significant metabolic risks that require monitoring, regardless of body weight:

• Insulin resistance — present in 50–70% of women with PCOS, even in those with a normal BMI. It drives many of the hormonal and metabolic features of the syndrome
• Glucose intolerance and type 2 diabetes — oral glucose tolerance testing (OGTT) is recommended at diagnosis and at regular intervals
• Dyslipidaemia — elevated triglycerides and LDL cholesterol, reduced HDL cholesterol
• Cardiovascular risk — higher lifetime risk of hypertension, metabolic syndrome, and cardiovascular events
• Non-alcoholic fatty liver disease (NAFLD) — increasingly recognised as part of the PCOS metabolic spectrum

Treatment

Management of PCOS is multifaceted and tailored to the individual’s primary concerns — whether that is irregular periods, cosmetic symptoms, fertility, or metabolic health:

• Lifestyle modifications — the cornerstone of PCOS management. Even a modest weight loss of 5–10% in overweight patients can significantly improve hormonal profiles, restore ovulation, and reduce metabolic risk. Regular physical activity (both aerobic and resistance training) improves insulin sensitivity independently of weight loss
• Combined oral contraceptive pill — regulates cycles, reduces androgen levels, protects the endometrium from hyperplasia, and improves acne and hirsutism
• Anti-androgens — spironolactone or cyproterone acetate can be added for persistent hirsutism or acne (always used with reliable contraception)
• Metformin — improves insulin resistance and may help restore regular ovulation, particularly in women with glucose intolerance
• Inositol (myo-inositol and D-chiro-inositol) — a well-tolerated supplement that may improve insulin sensitivity and ovarian function

PCOS and fertility

PCOS is one of the most common causes of anovulatory infertility, but the outlook is generally favourable with appropriate treatment:

• Lifestyle optimisation — often the first step, as weight management and exercise alone can restore ovulation in many women
• Ovulation induction — letrozole is now the first-line medication, followed by clomifene citrate. These treatments are monitored with ultrasound to ensure a safe response
• Gonadotrophins — injectable hormones used when oral medications are unsuccessful, with careful monitoring to minimise the risk of multiple pregnancies
• Ovarian drilling — a laparoscopic procedure that can restore spontaneous ovulation in women who do not respond to medication
• IVF — reserved for cases where other treatments have failed or when additional fertility factors are present