Key Takeaways
  • PCOS affects 12–21% of women of childbearing age — many of whom are never formally diagnosed
  • It is caused by hormone imbalance and insulin resistance, and is strongly linked to overweight and obesity
  • PCOS and obesity form a bidirectional cycle — each worsening the other
  • Diagnosis requires at least two of three criteria: irregular periods, raised androgens, or polycystic ovaries on ultrasound
  • Weight loss is one of the most effective treatments for PCOS — improving hormonal balance, fertility, and metabolic health

What Is PCOS?

12–21%
of women of childbearing age are thought to have PCOS
Many are never formally diagnosed — making it one of the most underdiagnosed hormonal conditions in Australia

Polycystic Ovarian Syndrome (PCOS) is a common hormonal condition characterised by an imbalance in reproductive hormones and, in many cases, insulin resistance. It affects women across a wide range of body weights — it is not exclusively a condition of people with obesity — but excess weight significantly worsens its symptoms and progression.

PCOS is associated with a broad range of health problems including irregular menstrual cycles, excess facial and body hair (hirsutism), acne, reduced fertility, overweight and obesity, and an increased risk of metabolic syndrome and Type 2 Diabetes.

The PCOS–Obesity Cycle

The relationship between PCOS and body weight is bidirectional and self-reinforcing — one of the reasons many women with PCOS find it so difficult to lose weight, and why untreated weight gain tends to worsen their symptoms.

The bidirectional cycle
How PCOS and obesity reinforce each other:
The hormone imbalances of PCOS (elevated androgens, insulin resistance) promote fat storage and make weight loss harder
Excess adipose tissue increases insulin resistance and raises androgen levels, which worsens PCOS symptoms
Worsening PCOS further disrupts hormonal balance, making weight management even more difficult
Breaking this cycle — through effective weight loss — can produce dramatic improvements in PCOS symptoms and metabolic health

Symptoms of PCOS

PCOS presents differently in different women. Some have multiple symptoms; others have very few. Common symptoms include:

Periods more than 35 days apart (oligomenorrhoea)
Absence of periods (amenorrhoea)
Subfertility or difficulty conceiving
Thick, coarse hair on the face or body (hirsutism)
Thick, dark skin patches (acanthosis nigricans) on neck, groin, or underarms
Acne, particularly along the jawline
Thinning scalp hair or female-pattern hair loss
Overweight or obesity — particularly around the abdomen

How Is PCOS Diagnosed?

A formal diagnosis of PCOS requires meeting at least two of the following three criteria (known as the Rotterdam criteria):

1

Irregular or absent periods

Oligomenorrhoea (cycles >35 days) or amenorrhoea (no periods)
2

Elevated androgen (male) hormones

Either confirmed on blood testing, or evident clinically through symptoms such as hirsutism, acne, or hair loss
3

Polycystic ovaries on ultrasound

Presence of multiple small follicles on one or both ovaries, identified on pelvic ultrasound
✓ You need at least 2 of these 3 criteria for a diagnosis — you do not need all three, and you do not need to have ovarian cysts to be diagnosed with PCOS.

How Is PCOS Managed?

Treatment for PCOS is highly individualised — the right approach depends on your specific symptoms, whether you are trying to conceive, and your overall metabolic health. There is no one-size-fits-all solution, but a number of evidence-based options are available.

Weight loss is one of the most effective interventions for PCOS in women with overweight or obesity. Even a modest reduction in body weight — as little as 5–10% — can significantly improve hormonal balance, restore menstrual regularity, improve fertility, reduce androgen levels, and lower the risk of metabolic complications. It addresses the root driver of the PCOS–obesity cycle rather than just managing individual symptoms.

If you are concerned you may have PCOS, our doctors at MedSurg Weight Loss can assess you, support a formal diagnosis, and help you develop an individualised treatment plan. For women whose PCOS is linked to overweight or obesity, weight management is often central to that plan. Book an appointment or learn more about our Women's Health and Medical Weight Loss services.

Medical disclaimer: This article is for general educational purposes only. PCOS is a complex condition that requires individual assessment and management. Please consult your doctor for personalised advice about symptoms, diagnosis, and treatment.

Topics: Women's Health PCOS Metabolic Health Medical Weight Loss Hormones
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