How a simple blood test offers an easy, accurate objective alternative to Transvaginal Ultrasound to simplify PCOS diagnosis

Could a new alternative to ultrasound create standardised diagnostic criteria for PCOS and help millions of women achieve their desired family size?

Polycystic Ovary Syndrome (PCOS) is the most common endocrine disorder in reproductive-aged women, affecting 6-13% of women globally regardless of ethnicity¹. Yet women must often wait years for diagnosis – delaying treatment and increasing the risk of long-term complications.

Challenge 1: Inconsistent application of the standardized diagnostic criteria

The first reason is a lack of universal agreement on diagnostic criteria, which often varies across different healthcare settings. A study of 160 Asia-Pacific clinicians found that only 8.8% used the correct combination of clinical and biochemical hyperandrogenism, menstrual disturbances and pelvic ultrasound to diagnose PCOS².

60.5% of respondents were unable to correctly identify PCOS clinical features, while just 31% of clinicians from family medicine, 19.2% from endocrinology and 11.6% from general practice reported having a standardised workplace protocol to diagnose PCOS².

The Rotterdam criteria, a widely accepted standard requiring the presence of two out the following three features, relies on multiple and often subjective measures³:

• Oligo- or anovulation
• Clinical or biochemical hyperandrogenism
• Polycystic ovarian morphology (PCOM)

Challenge 2: Challenges of reliably identifying PCOM using transvaginal ultrasound

Transvaginal Ultrasound, used to identify PCOM, presents a particular challenge. There are no consistent standards for establishing the cutoff count for follicles.

As a woman’s age goes beyond 35 years – the appearance of her ovaries may change because of how the ovaries age throughout a woman’s lifespan,” explains Adj. Prof. Zhongwei Huang.

Importantly, when we make a diagnosis, one of the latest clinical practice guidelines states that adolescents must be at least eight years post menarche to even consider a PCOS diagnosis. 

Because most of the time these girls are young, they have good ovarian reserves and sometimes the ovaries will appear multicystic. And that sometimes will cause confusion for clinicians when they come to interpret an ultrasound.”

Transvaginal ultrasounds (TVUS), currently the preferred approach to evaluate PCOM, are also time-consuming and require expert sonographic skills, as well as other limitations::

1. TVUS is not suitable for sexually inactive women and may cause discomfort or distress.
2. Reliability in detecting PCOM is reduced among women with higher body mass index — a common characteristic in PCOS.
3. Interpretation is subjective; TVUS assessments are prone to substantial and well-recognized interobserver variability.

Challenge 3: The underrecognised metabolic link

The second challenge in PCOS diagnosis is the intrinsic, often under recognised link between reproductive and metabolic health.

“Prenatal factors, genetic variation, epigenetic mechanisms, unhealthy lifestyles and environmental toxins may all contribute to symptoms similar to PCOS in susceptible women,” adds Adj. Prof. Zhongwei Huang.

Studies suggest obesity is strongly associated with PCOS, increasing and multiplying the effects of androgens in women⁴. Patients with PCOS are three times more likely to experience hirsutism, 50% reduced globulin [sex hormone] binding levels and a fivefold increase in free androgen index⁵.

“Obesity is not one of the diagnostic criteria for PCOS, but around 50-80% of PCOS patients are obese,” says Prof. Emerita Tasnim Ahsan. “Around 75% have insulin resistance, and type 2 diabetes risk is increased by three to 10 times. Dislipidemia is present in about 70% of the cases and metabolic syndrome has a prevalence two times higher than in the background population.”

How AMH provides an objective, accessible, accurate & reliable method for PCOS diagnosis:

Now, a new solution addresses the diagnostic variability challenge: a simple blood test. Anti-Müllerian Hormone (AMH), a hormone produced by small antral follicles in the ovaries, reflects the number of developing follicles in the ovary and is often used as a marker of ovarian reserve.

“AMH is fairly stable over reproductive age,” says Prof. Eu Leong Yong. “And if you have high AMH, aromatase activity [which converts androgens into oestrogens, crucial for follicle maturation and ovulation], decreases. 

In a 2015 paper published in the Journal of Clinical Endocrinology, we found that for every 14% increase in AMH levels, the menstrual cycle length increases by one day. It’s a straight line relationship; high AMH equals long cycles. 

So we’re therefore able to use AMH as a proxy for antral follicle count. We found that AMH is able to replace transvaginal ultrasound for PCOS diagnosis with a high degree of overlap.” 

The results show that serum AMH levels, measured using a reliable immunoassay, can define PCOM in adult women. This gives clinicians a consistent and repeatable metric to diagnose PCOS alongside the other two Rotterdam criteria, and circumvents the need for invasive or subjective ultrasound interpretation. 

The key, says Dr. Nandita Palshetkar, is to account for both reproductive and metabolic health. “The profile of the patient is very important. Her age, BMI, metabolic risks, phenotype, AFC and AMH. All these things should be identified. Lab variability exists, so use the same lab for AFC and AMH where possible and be aware of local assay ranges.”

Early detection can empower millions of women

With a more confident, earlier diagnosis, the clinical focus can pivot immediately to comprehensive management. This strategy begins with addressing the metabolic phenotype through lifestyle optimisation, nutrition and weight management and the judicious use of agents like metformin where insulin resistance is evident.

Destigmatising the language used in diagnosis is a vital first step. “PCOS diagnoses are strongly linked to anxiety and depression,” says Prof. Eu Leong Yong. “We want to change the message we put across, particularly in PCOS Awareness Month. We want to say ‘you’re wealthy, because you have a lot of eggs, and if you get treatment early, you can achieve your desired family size’”. 

In short: early diagnosis of PCOS is key to timely treatment, which can help to avoid severe reproductive, metabolic and psychological complications. But current methods leave women waiting too long. Patients are often required to make multiple visits to specialists, referred between teams again and again. AMH immunoassays are a simpler solution – helping clinicians reach more accurate objective diagnoses more quickly.

If health systems across Asia-Pacific can adopt a unified approach to AMH, we can significantly improve patient outcomes for women living with PCOS: improved ovulation, regular cycles, reduced symptoms, and lower risks for long-term health issues like type 2 diabetes, heart disease and endometrial cancer. And ultimately, we can help millions of women achieve their desired family size along with better management of metabolic complications.