PCOS and Hormone Health

The most common misunderstanding about PCOS was built into its name. It is not a disease of ovarian cysts. The structures counted on an ultrasound are follicles, ordinary immature eggs, present in greater number than usual. A normal-looking scan does not rule the condition out, and a polycystic-looking ovary on its own does not rule it in. What this actually is, is a metabolic and endocrine condition that involves the ovaries, which is why an endocrinologist rather than only a gynaecologist is often the right person to manage it.

The name has now changed for exactly that reason. On 12 May 2026 an international consensus process renamed the condition polyendocrine metabolic ovarian syndrome, or PMOS. Monash University, which hosts the international guideline, describes 56 patient and professional organisations taking part, more than 22,000 survey responses, and a three year transition that completes with the 2028 guideline update. This library keeps PCOS as the primary term, because it is the term patients, referring clinicians and search engines still use.

What this area actually covers

Diagnosis rests on the Rotterdam framework: two of three features, being irregular or absent ovulation, androgen excess shown clinically or on blood tests, and polycystic ovarian morphology, with other causes excluded first. The World Health Organization's fact sheet, updated on 22 January 2026, estimates that 10 to 13 percent of women globally have the condition and that up to 70 percent of those affected are undiagnosed. Monash puts it at one in eight women, more than 170 million worldwide.

This topic also carries the androgen and pituitary questions that sit next to PCOS without being PCOS: a raised DHEA-S, which points at the adrenal gland rather than the ovary, a high prolactin, which has its own workup, and low testosterone in men, which is a separate clinical problem with a separate protocol.

Where the standard workup goes wrong

Four errors account for most misdiagnosis. Testosterone drawn while a woman is taking a combined oral contraceptive, which suppresses the result and hides the finding it was ordered to detect. An ultrasound ordered when the other two Rotterdam features are already present, where it cannot change the answer. A diagnosis made without excluding thyroid disease, high prolactin and non-classic congenital adrenal hyperplasia, which is a requirement rather than a formality. And adolescents labelled from a scan, when normal adolescent ovaries frequently look polycystic.

There is also a treatment-side error. Because irregular periods are the most visible feature, treatment often stops once bleeding is regular. Regular withdrawal bleeding on the pill is not the same as a corrected metabolic picture, and it is the metabolic picture that carries the long-term risk.

How to think about the decisions

Treatment follows the goal, not the label, which is why two women with the same diagnosis reasonably end up on different medications. If the goal is cycle regularity and endometrial protection, combined hormonal contraception is first line. If it is androgen symptoms, the anti-androgen route applies, on reliable contraception. If it is pregnancy, ovulation induction is the pathway and contraception is obviously not. If it is metabolic risk, the work is insulin sensitivity, body composition, sleep and blood pressure, and that work applies at any body weight, since the lean phenotype carries metabolic risk too.

The diagnostic criteria themselves remain genuinely contested. The Androgen Excess and PCOS Society argued in its task force report that this should be defined as a predominantly hyperandrogenic syndrome, meaning androgen excess should be required rather than optional. The 2023 international guideline kept the Rotterdam framework. Under one definition a woman with irregular cycles and polycystic ovaries but no androgen excess has the condition; under the other she does not. That disagreement is why two specialists can read the same file differently, and it is worth knowing about before assuming one of them is wrong.

What changed recently

The 2023 International Evidence-Based Guideline, which carries 77 evidence-based and 54 consensus recommendations plus 123 practice points, made two changes that alter what gets ordered. Anti-Mullerian hormone can now be used as an alternative to ultrasound for the ovarian morphology criterion, in adults only. And in adolescents, both ultrasound and AMH are excluded from the diagnostic criteria because they lack specificity at that stage: an adolescent needs both irregular cycles and hyperandrogenism, and one feature alone places her in an "at risk" category to be followed rather than labelled.

The answers below start with diagnosis, move through the metabolic link and the treatment options, then cover fertility, skin and hair, and long-term risk. If you are trying to work out whether you meet the criteria, use the table above first.