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Why The Lancet Renamed PCOS to PMOS in 2026

The fourteen-year global consensus process behind the renaming of one of the most common endocrine conditions affecting women — and what it means in practice.

By Dr Gautam V. DaftaryDirector, Aksigen IVF

Last reviewed June 20267-minute read1,575 words

The condition formerly called polycystic ovary syndrome — PCOS — has a new name. It is now polyendocrine metabolic ovarian syndrome, or PMOS¹, and the change was the result of a fourteen-year consensus process led by Monash University in Australia, involving fifty-six leading academic, clinical, and patient organisations across six continents and more than 22,000 survey responses from patients and clinicians.

The decision was published in The Lancet on May 12, 2026, by a team led by Professor Helena Teede of Monash and Professor Terhi Piltonen of the International Androgen Excess and Polycystic Ovary Syndrome Society. Within two weeks, the American Society for Reproductive Medicine² and the Endocrine Society³ had both formally endorsed the new name, and adoption was underway across international clinical guidelines.

This is one of the largest renaming exercises in the history of medical nomenclature. For the roughly 170 million women worldwide who live with the condition — including approximately 44 million in India⁴ — it is a moment worth understanding.

What Changed

The new name has three components, and each is doing a specific piece of work.

Polyendocrine acknowledges that the condition involves multiple hormonal systems, not just one. The pituitary, the adrenals, the pancreas, and the ovaries all play a role; so do insulin, the androgens, the gonadotropins, and the brain's neuroendocrine signalling. The old name attached the condition to the ovaries alone. The new name names what is actually going on biologically.

Metabolic names the dimension that has been most neglected under the old framing. The condition is fundamentally a metabolic disorder. Insulin resistance, weight regulation difficulty, dyslipidaemia, glucose intolerance, and elevated cardiovascular risk are all part of the condition, not separate complications of it. Women with PMOS face two to three times the risk of gestational diabetes, type 2 diabetes, and hypertensive complications of pregnancy compared with women without the condition. The new name embeds this in the diagnosis itself rather than treating it as something to discover later.

Ovarian retains the connection to ovulatory disturbance, which remains a defining feature and the reason most women come to a specialist. But it is the third word in the new name, not the first. The reproductive dimension is real and continues to matter; it is no longer the only frame.

This is the principle the consortium worked toward — a name that is biologically accurate, clinically useful, and patient-respectful. Eighty-six percent of patients and 71 percent of clinicians who participated in the consultation supported the change.

Why Now

The case for renaming PCOS had been building for two decades. The original 1935 name — coined by American gynaecologists Irving Stein and Michael Leventhal, who described polycystic ovaries in seven women with menstrual irregularity — was anchored in what could be seen on surgical inspection of the ovary at the time. Eighty years of subsequent biology revealed the limits of that framing.

The cysts were not cysts. They were immature follicles arrested in development — a downstream consequence of the underlying hormonal disturbance, not its cause. Some women diagnosed with PCOS had no detectable cysts on ultrasound; some women with cysts had no underlying syndrome. The name described a feature that was neither universal nor causal.

More consequentially, naming the condition after its ovarian feature pulled clinical attention toward fertility and away from metabolism. Women diagnosed with PCOS in their twenties were routinely treated for cycle irregularity or infertility, then surprised in their forties to learn they had developed type 2 diabetes or cardiovascular disease at unusually young ages. The metabolic story was being missed.

Three threads converged to make 2026 the moment. The first was the 2023 International Evidence-Based PCOS Guideline⁵, which formally established the metabolic dimension as central to diagnosis and management. The second was sustained patient advocacy — Verity (PCOS UK) and similar organisations had been calling for a rename for years. The third was the readiness of major medical societies, including ASRM and the Endocrine Society, to formally endorse a coordinated change.

How the Rename Happened

The renaming was not a unilateral decision by one institution. It was the output of a structured fourteen-year consensus process — among the most ambitious naming exercises ever attempted in medicine.

The process was led by Professor Helena Teede of Monash Centre for Health Research and Implementation, with Professor Terhi Piltonen as co-lead representing the International Androgen Excess and PCOS Society, Anuja Dokras as the Society's Executive Director, and Rachel Mormon as Chair of Verity (PCOS UK)1. Fifty-six leading academic, clinical, and patient organisations participated, including the American Society for Reproductive Medicine, the Endocrine Society, the European Society of Endocrinology, and the European Society of Human Reproduction and Embryology, alongside similar national societies across six continents.

The methodology was rigorous. The consortium ran iterative global surveys that gathered more than 22,000 responses from patients and multidisciplinary health professionals across all world regions. They held workshops with patient representatives and clinicians. They tested candidate names against principles of scientific accuracy, clarity, stigma avoidance, cultural appropriateness, and implementation feasibility. They explicitly prioritised biological accuracy over retaining a familiar acronym.

A companion paper published alongside the rename specifically addressed the adolescent voice in the process⁶, recognising that PMOS often presents first in adolescence and that adolescent patients have historically been excluded from disease-naming conversations. Adolescent input was integrated through structured consultation.

What Happens Now

The rename triggered a coordinated implementation process designed to take three years across 195 countries.

International clinical guidelines will be updated first. The 2023 International Evidence-Based PCOS Guideline, the operating reference for most specialists, is expected to be reissued as the PMOS Guideline in late 2026 or 2027. The core clinical content — diagnostic criteria, treatment recommendations, management of associated conditions — will remain substantially the same, because the underlying science has not changed. What changes is the framing.

International Classification of Diseases (ICD) codes will follow. The current ICD-10 code for PCOS (E28.2) will be updated to reflect PMOS terminology, affecting medical records, insurance coding, and statistical reporting across health systems worldwide. The expected timeline is 2027 to 2028.

Medical school curricula are updating alongside. The Royal College of Obstetricians and Gynaecologists in the United Kingdom and similar bodies have already begun. In India, the change is expected to be incorporated through the Federation of Obstetric and Gynaecological Societies of India and similar professional bodies over the coming year.

Most consumer-facing health information will follow the institutional changes. Mayo Clinic, Cleveland Clinic, NHS, and similar resources have begun updating their content. Search engines will recognise PMOS and PCOS as the same condition for the foreseeable future, so patients searching either term will continue to find relevant information.

What This Means in India

The Indian context for the rename is particular. PMOS affects approximately 19.6 percent of Indian women aged 18 to 404 — substantially higher than the 10 to 13 percent global figure — and the phenotype distribution in India differs from Western cohorts, with phenotype C (hyperandrogenism plus polycystic ovarian morphology in women with apparently regular cycles) the most common at 40.8 percent.

The implication is that the new framing matters more, not less, in India. A condition that affects roughly 44 million Indian women — and that frequently presents without the menstrual irregularity that prompts evaluation in Western clinical practice — needs naming that reflects its full clinical picture. Under the old name, many Indian women with PMOS went undiagnosed because their cycles appeared normal. Under the new name, with metabolism explicitly named in the condition, the diagnostic conversation has a better chance of beginning at the right place.

Implementation in India is expected to track the international rollout closely. Indian professional societies — the Federation of Obstetric and Gynaecological Societies of India, the Indian Society for Assisted Reproduction, the Endocrine Society of India — are part of the coordinated adoption process.

What Stays the Same

For patients, three things do not change.

If you were diagnosed with PCOS, you have PMOS. The condition is the same. No new diagnosis is required, and no new investigation is needed to confirm what you already know.

Your treatment continues. Whatever combination of lifestyle measures, metformin, hormonal contraception, ovulation induction, or other intervention you are currently on remains appropriate. The 2023 International Guideline that drives clinical practice has not been retracted; it has been carried forward into the new framework.

Your medical team continues. The specialists who have been managing your condition under the PCOS name are equally able to manage it under the PMOS name. The science is unchanged. Only the framing has shifted.

For readers wanting the comprehensive clinical picture — what PMOS actually is, how it shows up, how it is diagnosed and treated, and what it means for fertility, pregnancy, and long-term health — the Bharat Daftary Knowledge Centre's pillar article on Understanding PMOS is the next read.

About the Author

Dr Gautam V. Daftary is Director of Aksigen IVF and a senior consultant in reproductive medicine. He is a senior author on the 2026 review of PCOS / PMOS in the Indian context published in Insights in Reproductive Medicine.

This article is part of the Bharat Daftary Knowledge Centre, the patient-education programme of Aksigen IVF. It is intended for general information and does not replace consultation with a qualified clinician.

References

Teede HJ, Bahri Khomami M, Morman R, et al.Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome: a multistep global consensus process.The Lancet. Published online May 12, 2026. DOI: 10.1016/S0140-6736(26)00717-8.
American Society for Reproductive Medicine.PCOS is Now PMOS: Understanding the Name Change.ASRM official statement, May 27, 2026.
Endocrine Society.Polyendocrine Metabolic Ovarian Syndrome: New name to improve diagnosis and care of condition affecting 170 million women worldwide.Endocrine Society official statement, 2026.
Ganie MA, Chowdhury S, Suri V, Joshi B, Bhattacharya PK, Agrawal S, et al.Prevalence, phenotypes, and comorbidities of polycystic ovary syndrome among Indian women.JAMA Network Open.ICMR-PCOS National Task Force, n = 9,824.
Teede HJ, Tay CT, Laven J, Dokras A, Moran LJ, Piltonen TT, et al., on behalf of the International PCOS Network.Recommendations from the 2023 International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome.Human Reproduction.2023;38(9):1655–1679. DOI: 10.1093/humrep/dead156.
Cree M, Piltonen TT, Dokras A, et al.From PCOS to PMOS: inclusion of the adolescent voice in setting clinical and research priorities.The Lancet.Companion comment to the rename paper, 2026.

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