Polycystic Ovary Syndrome (PCOS) is a common hormonal disorder affecting many women in Australia. Ultrasound imaging often comes up in discussions about PCOS diagnosis and management, but its role is more nuanced than many realise. This blog explains the current understanding and guidelines around PCOS ultrasound use in Australia, helping women and healthcare providers make informed decisions.
What Is PCOS Ultrasound?
A PCOS ultrasound is a pelvic scan that examines the ovaries to identify features associated with PCOS, primarily:
- The presence of multiple small follicles (often called “cysts”) on the ovaries
- Increased ovarian volume
Traditionally, having 20 or more follicles in an ovary or an ovarian volume greater than 10 millilitres has been considered indicative of polycystic ovarian morphology (PCOM).
The Role of Ultrasound in Diagnosing PCOS in Australia
Recent Australian-led international guidelines, including the 2023 evidence-based PCOS guideline led by Monash University and collaborators, have refined the role of ultrasound in diagnosis:
- Ultrasound is not required for diagnosis if a woman has both irregular menstrual cycles and signs of elevated male hormones (hyperandrogenism). Around 70% of women with PCOS fall into this category, so ultrasound is often unnecessary.
- For women with only one of these features (either irregular cycles or hyperandrogenism), ultrasound or blood tests measuring anti-Müllerian hormone (AMH) levels may be used to support diagnosis.
- In adolescents (within 8 years of menarche), ultrasound is generally not recommended for PCOS diagnosis. This is because many young women naturally have multifollicular ovaries, which can mimic PCOM and lead to overdiagnosis. Instead, diagnosis relies on clinical features like hyperandrogenism and ovulatory dysfunction.
- Transvaginal ultrasound is the preferred method in sexually active adult women for accurate ovarian assessment. Transabdominal ultrasound is less precise but may be used when transvaginal is not possible.
- Ultrasound criteria for PCOM are evolving with advancing technology, and age-specific cut-offs are being developed.
Why Ultrasound Alone Is Not Enough
Research and clinical experience in Australia have shown that many women without PCOS may have polycystic-looking ovaries on ultrasound. Up to 70% of young women can have polycystic ovarian morphology without having PCOS. Therefore, relying solely on ultrasound can lead to overdiagnosis and unnecessary anxiety.
What Happens During a PCOS Ultrasound?
- Transvaginal Ultrasound: A probe is gently inserted into the vagina to obtain detailed images of the ovaries and uterus. This approach provides the most accurate assessment of follicle count and ovarian volume.
- Transabdominal Ultrasound: A probe is moved over the lower abdomen. This is less invasive but less detailed, often used for women who are not sexually active or prefer this method.
The scan usually takes about 15-30 minutes and is performed by a trained sonographer.
What Does Ultrasound Tell You?
Ultrasound helps identify:
- The number and size of ovarian follicles
- Ovarian volume
- Presence of cysts or other abnormalities
- Helps rule out other pelvic conditions
However, it is only one part of the diagnostic puzzle alongside clinical symptoms and blood tests.
Accessing PCOS Ultrasound in Australia
Ultrasound services are widely available through public hospitals, private clinics, and specialised women’s health centres. Referral from a GP or specialist is usually required. Many women also access ultrasound as part of fertility assessments.
In Australia, ultrasound plays a supportive role in PCOS diagnosis but is not mandatory in many cases, especially when clinical signs of PCOS are clear. The 2023 international evidence-based guidelines, led by Australian researchers, emphasise a balanced approach to avoid overdiagnosis and ensure accurate, patient-centred care.