How PCOS Is Diagnosed: What to Expect at the GP

Polycystic Ovary Syndrome (PCOS) is one of the most common hormonal conditions, affecting around 1 in 10 people with ovaries. But getting a diagnosis isn’t always quick or straightforward. It can take months (or even years) for people to understand what’s going on, especially if their symptoms are brushed off or misunderstood.

So if you’re wondering whether you might have PCOS, or you’ve been told to get tested, here’s a clear breakdown of what the process usually involves, and what questions you can ask at each stage.

First Step: The GP Appointment

Your GP is often the first point of contact. They’ll ask questions about your:

• Menstrual cycle: Is it irregular, very heavy, or infrequent?

• Skin and hair changes: Acne, facial/body hair, or thinning scalp hair.

• Fertility: Whether you're trying to conceive or not, they may ask about past pregnancies or cycle tracking.

• Other symptoms: Fatigue, weight changes, mood swings, or cravings.

You don’t need to bring a diagnosis, just be honest about what you’re noticing in your body. That said, tracking your symptoms can make a real difference when speaking to your GP. It helps build a clearer picture over time and makes it easier to notice patterns you might otherwise miss.

You can jot things down in a notebook, use your phone’s calendar, or try a free period or symptom-tracking app. Note when your period starts and ends, how long your cycles are, any spotting, changes in skin or hair, mood shifts, or anything that feels out of the ordinary. Even just a few months of notes can give your GP something more concrete to work with, and it puts you in the driver’s seat of your own care.

The Diagnostic Criteria: What Doctors Look For

In the UK, PCOS is diagnosed using the Rotterdam Criteria. To receive a formal diagnosis, a person needs at least two of the following three:

1. Irregular or no ovulationThis includes long gaps between periods, missing periods, or not ovulating even if you bleed.

2. Signs of high androgensThis could be:

   • Physical signs: Acne, excess hair growth (hirsutism), or scalp hair thinning.

   • Blood tests: Showing high levels of testosterone or DHEA-S.

3. Polycystic ovaries on an ultrasoundThe ovaries appear larger and contain many small fluid-filled follicles (often called “cysts,” though they’re actually follicles that haven’t matured).

You only need two out of three. For example, if you have irregular periods and excess androgens, you may not need an ultrasound to be diagnosed.

Blood Tests: What They're Checking

Your GP may order a set of blood tests to rule out other conditions and assess hormone levels. These may include:

• Testosterone and DHEA-S – Androgen levels

• LH and FSH – To check how the brain is signalling the ovaries

• Prolactin – To rule out other hormone disorders

• TSH – To check thyroid function

• Glucose and insulin – To assess for insulin resistance

• Lipid profile – Cholesterol and triglyceride levels

Not all tests are run at once, and you may be asked to repeat them if results are borderline or if they vary based on where you are in your cycle.

Ultrasound Scan: What to Expect

A pelvic ultrasound may be offered to look at your ovaries and uterine lining. This can be done:

• Transvaginally (internal scan) – A small probe is inserted into the vagina for a clearer image.

• Abdominally – A probe is moved across the lower belly. This is usually used if you’re a teenager, haven’t had penetrative sex, or prefer a non-invasive method.

They’ll look for 12 or more small follicles arranged in a ring, or an ovary that’s enlarged.

Important: Having polycystic ovaries doesn’t automatically mean you have PCOS. Some women have that appearance but no symptoms. Others have all the symptoms but normal-looking ovaries.

What Happens After the Tests?

Once your results are in, your GP or a specialist will review the full picture, test results, symptoms, and scan findings, to confirm whether PCOS is the most likely explanation.

From there, they’ll talk through management options, which may include:

• Regulating periods (e.g. with the pill or other hormonal methods)

• Managing acne or excess hair

• Supporting fertility (if relevant)

• Addressing insulin resistance or metabolic risk

• Mental health support or lifestyle guidance

You may be referred to an endocrinologist, dermatologist, or gynaecologist depending on your symptoms.

When Diagnosis Gets Missed or Delayed

Some people are told these are ‘normal’ things that can ‘work themselves out’.

These responses are dismissive and unhelpful. PCOS is a medical condition that deserves care, regardless of your age or body size.

If you feel your symptoms aren’t being taken seriously, it’s okay to:

• Ask for a second opinion

• Request specific tests

• Bring someone with you to appointments

• Keep a symptom journal to back up what you're feeling

You know your body better than anyone, and you deserve answers.

In Summary

Diagnosing PCOS involves a combination of listening to your symptoms, checking hormone levels, and sometimes doing an ultrasound. You don’t need to fit a perfect “textbook” case to get help. If your cycle feels off, your skin or hair has changed, or you’re struggling with fertility or fatigue, it’s worth asking about PCOS.

Early diagnosis can help you manage symptoms, protect long-term health, and feel more in control of your body.