Guide · updated 16 May 2026

What is PMOS? Clear, sourced definition

PMOS stands for Polyendocrine Metabolic Ovarian Syndrome — the new international name for PCOS, officially introduced in May 2026. It is the same syndrome, with a name that finally reflects its reality: hormonal, metabolic, ovarian, and well beyond the ovaries alone.

Information, not a diagnosis. This page provides general guidance. It does not constitute a diagnosis and does not replace a personalised medical consultation.

What is PMOS?

For decades, the condition was known as polycystic ovary syndrome — a name centred on “cysts” that are not true cysts, and on the ovaries, when the syndrome affects many other body systems. On 12 May 2026, a publication in The Lancet and an announcement from the Endocrine Society officially introduced the new international name: PMOS.

Breaking down the acronym PMOS:

Poly-endocrine — multiple hormonal disruptions coexist and interact: insulin, androgens (testosterone, DHEAS), and the LH/FSH axis hormones. It is not a single-hormone disorder — it is a whole system.
Metabolic — insulin resistance is a central mechanism, present in a large proportion of affected women. It raises the risk of type 2 diabetes and cardiovascular disease.
Ovarian — ovarian dysfunction (irregular cycles, anovulation) remains a defining feature. But it is no longer the only dimension of the syndrome.

According to the Endocrine Society, this syndrome affects approximately 1 in 8 women worldwide — over 170 million people. The WHO estimates prevalence at 10–13% of women of reproductive age, with up to 70% still undiagnosed.

Why was the name changed?

The international consensus that led to the May 2026 renaming involved over 22,000 responses to a global survey, dozens of professional and patient organisations, and eleven years of work coordinated by the Monash University team (Australia). Several reasons drove the change:

What were called “cysts” are actually follicles awaiting maturation — not true cysts. Many affected women do not have them at all.
The “polycystic” label implied a purely gynaecological problem, when the syndrome is multi-systemic.
PMOS affects skin (acne, hirsutism, hair loss), metabolism (insulin resistance, weight, cardiovascular risk), mental health (3–4 times higher risk of anxiety and depression compared to the general population), and fertility.
The old name delayed diagnoses in women who “did not have cysts” or had apparently normal cycles.
The new name, PMOS, puts the whole body at the centre and makes the syndrome more legible for patients and clinicians alike.

How do I know if I might be affected?

PMOS presents differently in different people. Four broad symptom areas can be indicators — alone or in combination:

Irregular cycles: spaced out (more than 35 days), very short, or absent for more than 3 months without another obvious cause.
Signs of clinical hyperandrogenism: persistent acne (especially chin and jawline), excess body or facial hair (hirsutism), hair thinning at the hairline.
Metabolic changes: insulin resistance, difficulty managing weight (especially abdominal), post-meal fatigue, sugar cravings.
Fertility difficulties: chronic or irregular anovulation, unsuccessful attempts to conceive.

These symptoms point in a direction, but only a healthcare professional can assess their significance in your specific context. To organise what you are experiencing before an appointment, the appointment preparation tool can help.

How is the diagnosis made?

Diagnosis is based on the Rotterdam criteria (2003, updated by the 2023 international guideline ): 2 out of 3 criteria are required.

Oligo-anovulation: irregular or absent cycles, indicating infrequent or absent ovulation.
Clinical or biochemical hyperandrogenism: acne, hirsutism, androgenic hair loss — or elevated testosterone / DHEAS on bloodwork.
Polycystic ovarian morphology on ultrasound, or elevated AMH: presence of numerous small follicles on the ovaries, or elevated anti-Müllerian hormone within the laboratory's reference range.

Before concluding PMOS, the clinician must rule out other conditions with similar symptoms: thyroid dysfunction (TSH), hyperprolactinaemia (prolactin), congenital adrenal hyperplasia (17-OH-progesterone), and Cushing's syndrome in atypical cases. The NHS provides detailed patient information on these steps.

What next?

Understanding what PMOS is marks a first step. Several resources on this site can support you further:

The name change in detail 10 myths debunked Prepare my appointment

Frequently asked questions

Are PMOS and PCOS the same thing?

Yes, exactly. PMOS is the new international name for PCOS since May 2026. The diagnostic criteria, management, and reality of the syndrome have not changed. If you were diagnosed with PCOS, you now have PMOS — no action is needed on your part.

Do you need to have cysts to be affected?

No. What are improperly called "cysts" are actually small ovarian follicles awaiting maturation, visible on ultrasound. Many people with PMOS do not have them at all. This is precisely one of the reasons the "polycystic" name was dropped: it was a source of confusion and delayed many diagnoses.

Is PMOS rare?

No — it is one of the most common endocrine syndromes. According to the Endocrine Society, approximately 1 in 8 women is affected worldwide, totalling over 170 million people. The WHO estimates its prevalence at 10–13% of women of reproductive age, with up to 70% still undiagnosed.

Who makes the diagnosis?

A GP can initiate initial tests (hormone panel, fasting glucose, symptom review). A gynaecologist or endocrinologist then takes over for detailed work-up, pelvic ultrasound, and diagnosis confirmation. A specialist nurse or nurse practitioner can also be a first point of contact, particularly for cycle and fertility questions.

Is PMOS a lifelong condition?

It is a chronic syndrome, which means it is managed over time rather than cured. Symptoms can fluctuate, improve during certain periods, and often ease after menopause. The goal is not to "defeat" the syndrome, but to understand it and manage it with appropriate follow-up: gynaecological, metabolic, and if needed, psychological.

Main sources

Page written from official public sources. It does not constitute a diagnosis or a treatment recommendation. For any medical decision, consult a healthcare professional.