Key Takeaways
Polycystic Ovary Syndrome (PCOS)
Polycystic ovary syndrome is a hormonal condition that affects the ovaries and can disrupt menstrual cycles, hormone levels, and metabolism. Despite its name, not everyone with PCOS has cysts on their ovaries. It is one of the most common endocrine disorders in people with ovaries during their reproductive years. A formal diagnosis requires meeting specific clinical criteria — not just one isolated symptom.
PCOS is formally diagnosed using the Rotterdam Criteria, which requires at least two of three features: irregular ovulation, elevated androgens (clinically or biochemically), and polycystic ovarian morphology on ultrasound.
Why the Name Can Mislead
The term "polycystic ovary syndrome" implies that cysts are central to the condition — but that framing is clinically imprecise. What ultrasound sometimes reveals are not true cysts but rather small, immature follicles that have stalled before ovulation. Their presence is one possible feature of PCOS, but it is neither required nor sufficient for a diagnosis on its own.
This naming problem contributes to widespread confusion. People may receive an ultrasound showing follicle clusters and assume they have PCOS — or, conversely, believe they cannot have the condition because their ovaries appear normal on imaging. Both assumptions can delay appropriate care.
PCOS is more accurately described as a syndrome of hormonal and metabolic dysregulation. The unifying thread across its presentations is disrupted ovarian function, often driven by elevated levels of androgens — hormones such as testosterone — which are typically present in smaller quantities in people with ovaries.
How PCOS Is Actually Diagnosed
The most widely accepted diagnostic framework is the Rotterdam Criteria, established by a consensus panel of reproductive specialists. Under this framework, a diagnosis of PCOS requires at least two of the following three features:
- Oligo- or anovulation — infrequent or absent ovulation, which typically presents as irregular or missing menstrual cycles.
- Clinical or biochemical signs of hyperandrogenism — elevated androgen levels detectable through blood tests, or physical signs such as excess facial or body hair (hirsutism), persistent acne, or scalp hair thinning.
- Polycystic ovarian morphology — a specific pattern identified on transvaginal ultrasound, defined by follicle count and ovarian volume thresholds.
Crucially, other conditions that mimic PCOS — including thyroid dysfunction, elevated prolactin, and congenital adrenal hyperplasia — must be ruled out before the diagnosis is confirmed. This is why PCOS cannot be self-diagnosed from symptoms alone.
Adolescent Diagnosis Requires Extra Care
Diagnosing PCOS in teenagers is more complex because irregular cycles and acne are common during puberty for reasons unrelated to PCOS. Many clinical guidelines recommend waiting until at least two years post-first menstruation before applying standard adult diagnostic criteria. If you are concerned about a teenager's symptoms, a paediatric endocrinologist or adolescent gynaecologist is the most appropriate starting point.
The Broader Health Picture
PCOS is not confined to reproductive health. Research consistently links the condition to a wider range of metabolic and psychological effects. Insulin resistance is common among people with PCOS, even those who are not overweight, and is thought to amplify androgen production by the ovaries. Over time, poorly managed insulin resistance raises the risk of type 2 diabetes and cardiovascular disease.
Mental health is also meaningfully affected. Studies show higher rates of anxiety and depression among people with PCOS compared to the general population — a pattern that may reflect both the biological effects of hormonal dysregulation and the psychological burden of managing a chronic, sometimes stigmatised condition.
For those concerned about related reproductive conditions, it is worth noting that PCOS and endometriosis are separate diagnoses with distinct mechanisms, though both can affect fertility. See our guide to endometriosis for a detailed explainer on that condition.
~10%
Estimated prevalence among reproductive-age women
The World Health Organization estimates PCOS affects approximately 8–13% of women of reproductive age globally, making it one of the most common hormonal disorders.
70%
Of cases that may go undiagnosed
Research published in reproductive medicine literature suggests up to 70% of people with PCOS may remain undiagnosed, often attributing symptoms to stress or normal variation.
Up to 80%
Of those with PCOS showing insulin resistance
Studies indicate that insulin resistance is present in a significant majority of people with PCOS, regardless of body weight, contributing to elevated metabolic risk.
What Management Can Realistically Achieve
There is no single treatment for PCOS — management is symptom-driven and shaped by an individual's reproductive goals, metabolic profile, and personal priorities. Healthcare providers may address menstrual irregularity, androgen-related symptoms, insulin resistance, and fertility support through different combinations of approaches.
Lifestyle factors — particularly physical activity and dietary patterns — are frequently discussed in clinical guidelines as tools for supporting insulin sensitivity and hormonal balance. These are general wellness supports, not cures, and their effect varies among individuals. Medications may also play a role, and any decisions about treatment should be made in consultation with a qualified provider.
For a deeper look at what the evidence does and does not support regarding PCOS management, see our companion piece on separating PCOS science from the noise.
Track Your Cycle Before Your Appointment
Keeping a record of your menstrual cycle length, regularity, and any associated symptoms for two to three months before seeing a healthcare provider can give your clinician valuable information. Apps or a simple calendar log both work well. This kind of documentation supports a more informed and efficient consultation.
This article is for general informational and educational purposes only and does not constitute medical advice. If you have concerns about symptoms, a diagnosis, or treatment options, please consult a qualified healthcare professional.