"Do I Have PCOS? Walking Through the Rotterdam Criteria"
Polycystic ovary syndrome (PCOS) affects somewhere between 6% and 13% of women of reproductive age. It remains one of the most under-diagnosed common conditions in medicine — average time to diagnosis from first symptom is over two years, with many women going through three or more clinicians before getting an answer.
Part of the problem is that PCOS doesn't have a single test. It's a clinical diagnosis based on a set of criteria — and which set of criteria varies by guideline. The most widely used internationally is the Rotterdam criteria, originally published in 2003 and updated in 2018.
The three Rotterdam criteria
You need to meet 2 of 3, with other causes excluded:
1. Oligo- or anovulation — irregular or absent periods. Specifically, cycles longer than 35 days or fewer than 8 cycles per year. Some women still have monthly bleeding without ovulating, but for most people this criterion shows up as cycles that are noticeably irregular or absent.
2. Hyperandrogenism — clinical OR biochemical signs of elevated androgens. Clinical means hirsutism (coarse dark hair on face, chest, abdomen, back in a male-pattern distribution), acne (especially adult-onset cystic acne along the jawline), or male-pattern scalp hair loss (thinning at the temples and crown). Biochemical means a blood test showing elevated total testosterone, free testosterone, or DHEAS.
3. Polycystic ovaries on ultrasound — defined as ≥20 follicles per ovary at modern (high-resolution) ultrasound, or ovarian volume ≥10 mL on either side. Note that the appearance of polycystic ovaries on ultrasound does not by itself diagnose PCOS — many women without PCOS have polycystic-appearing ovaries, and many with PCOS have normal-appearing ovaries.
You need 2 of 3. Common combinations:
- Irregular periods + hirsutism (criteria 1 + 2) → meets PCOS
- Irregular periods + polycystic ovaries (criteria 1 + 3) → meets PCOS
- Acne + polycystic ovaries (criteria 2 + 3) → meets PCOS
- Just irregular periods → does NOT meet PCOS by itself
- Just polycystic ovaries on ultrasound → does NOT meet PCOS by itself
Why "with other causes excluded" matters
The Rotterdam criteria require excluding other conditions that can mimic PCOS:
- Thyroid disease (especially hypothyroidism)
- Hyperprolactinemia (elevated prolactin)
- Late-onset congenital adrenal hyperplasia (a genetic enzyme deficiency)
- Cushing's syndrome (cortisol excess)
- Androgen-secreting tumors (rare but important to rule out, especially with rapid-onset symptoms)
This is why PCOS isn't a self-diagnosis — even with all three criteria met, a clinician needs to check a few labs to make sure something else isn't being missed.
Why the diagnosis matters
PCOS isn't just about cycles or cosmetic symptoms. Long-term, it's associated with:
- Insulin resistance and type 2 diabetes — substantially elevated lifetime risk
- Cardiovascular disease — elevated risk independent of other factors
- Endometrial cancer — chronic anovulation means continuous estrogen exposure without progesterone, raising risk over years
- Infertility — PCOS is the most common cause of anovulatory infertility
- Metabolic dysfunction — fatty liver, dyslipidemia, sleep apnea
All of these are addressable when caught early. Lifestyle changes, metformin, GLP-1 agonists, oral contraceptives (for cycle regulation and androgen suppression), and progestin therapy (to protect the endometrium) are all part of the modern PCOS toolkit.
The earlier the diagnosis, the more time there is to address these risks before they become complications.
What "shared decision-making" looks like with PCOS
Treatment isn't one-size-fits-all. The right plan depends on what you're trying to achieve:
- Want to get pregnant: ovulation induction (letrozole is first-line now, replacing clomiphene), possibly metformin
- Want regular cycles for symptom relief: hormonal contraceptives, cyclic progestin
- Want to address insulin resistance / weight: lifestyle program, metformin, GLP-1 receptor agonists in selected patients
- Want to manage hirsutism / acne: spironolactone often added to hormonal contraceptives; topical eflornithine; mechanical hair removal
- Want to protect the endometrium without daily medication: levonorgestrel IUD
A clinician who knows PCOS well will offer combinations, not a single recipe.
The conversation when you don't have a diagnosis yet
If you've had irregular cycles for years, if you struggle with hirsutism or persistent acne, if you've had fertility difficulties and PCOS hasn't been mentioned — it's worth bringing up explicitly. The phrase that works:
> "I've had irregular cycles since [age] and I've also had [hirsutism / acne / hair thinning]. I'd like to be evaluated for PCOS. Could we check my androgen panel and discuss whether I should have a pelvic ultrasound?"
That's the shape of the request. It anchors the visit on a specific question with a specific testing plan.
Skip the guesswork
The PCOS Self-Check tool walks you through the Rotterdam criteria based on what you already know about your symptoms, with the appropriate "you may meet 2 of 3" / "you meet 1, an ultrasound could change the picture" framing and clinical-handoff language. Same on-device privacy as the rest of /health — your answers don't leave the device.
The short version
PCOS is diagnosed by Rotterdam criteria: 2 of 3 (oligo/anovulation, hyperandrogenism, polycystic ovaries on ultrasound), with other conditions excluded. It's underdiagnosed because no single test catches it and the symptom picture varies. Long-term metabolic and cardiovascular risks make early diagnosis genuinely valuable. If irregular cycles + clinical androgen symptoms + no diagnosis is your story, it's a worth-asking-about conversation.