On 12 May 2026, a paper published in The Lancet by Teede, Tay, Piltonen, Dokras, Morman and colleagues, presented in parallel at the European Congress of Endocrinology in Prague, formally renamed polycystic ovary syndrome. The condition - which affects an estimated one in eight women globally, or more than 170 million people of reproductive age, and which has hitherto sat near the top of any reasonable list of conditions a UK Medical Licensing Assessment candidate must know cold — is now to be called polyendocrine metabolic ovarian syndrome, or PMOS. The change is the product of an eleven-year consensus process involving 56 patient and professional organisations, including the Endocrine Society, the International Androgen Excess and PCOS Society, ESHRE, and the UK patient charity Verity, with more than 22,000 survey responses contributing to its development. Coverage has been extensive: CNN, Time, Scientific American, Stat News and the American Journal of Managed Care all reported the change within days, and the New York-Presbyterian and Cleveland Clinic patient information pages had been updated by the third week of May. For working clinicians, the rename matters. For candidates approaching the Applied Knowledge Test and the MLA over the next three years, it matters in a more particular way: examinations, question banks, NICE Clinical Knowledge Summaries, GP curricula and electronic record templates will adapt at different rates, and the period of dual nomenclature will produce real ambiguity. Whether the renaming was wise, whether it goes far enough, and whether it goes in the right direction are all contested. None of those questions is closed.
What has changed, and what has not
The change is one of name, not of diagnostic substance. The 2023 International Evidence-Based Guideline for the Assessment and Management of PCOS, authored under the same Monash-led consortium and published by Teede, Tay, Laven and colleagues in Fertility and Sterility, retains its position as the operative diagnostic framework, and that framework still rests on the Rotterdam criteria as revised in 2003. In adults, diagnosis continues to require two of three: oligo- or anovulation, clinical or biochemical hyperandrogenism, and polycystic ovarian morphology on ultrasound or, alternatively under the 2023 update, elevated serum anti-Müllerian hormone, with other causes excluded - most importantly thyroid dysfunction, congenital adrenal hyperplasia, hyperprolactinaemia, androgen-secreting tumours and Cushing's syndrome. In adolescents, polycystic ovarian morphology and AMH retain their restricted role given the high prevalence of multi-follicular ovaries and irregular cycles in normal pubertal development. None of this has changed. What has changed is the conceptual centre of gravity. The name PMOS recasts the condition as a multisystem endocrine and metabolic disorder of which the ovarian phenotype is one component among several, alongside insulin resistance, hyperandrogenism, cardiometabolic risk, dermatological manifestations and the well-documented increase in anxiety and depression. The accompanying Lancet paper by the same group reports the absence of a true increase in abnormal ovarian cysts in affected women, undercutting one of the long-standing implicit clinical assumptions tied to the old name. Rollout is planned over three years, with updates anticipated to ICD-11, SNOMED CT, and clinical guidelines in 195 countries.
The case for renaming: scientific accuracy and the politics of underfunding
Two arguments dominate the case for the change, and both deserve to be taken seriously. The first is scientific. As Helena Teede and Terhi Piltonen have argued for over a decade, the old name was inaccurate in a way that mattered. Patients with the condition do not, in the pathological sense, have cysts: the ovarian morphology characteristic of the syndrome consists of an increased number of small antral follicles, not true cysts. The eponymous focus on the ovary has historically privileged the reproductive phenotype at the expense of the cardiometabolic burden, which on current evidence includes substantially elevated rates of type 2 diabetes, gestational diabetes, dyslipidaemia, hypertension and cardiovascular disease. The second argument is structural. Rachel Morman of Verity, the UK patient charity, and Anuja Dokras of the AE-PCOS Society have pointed out that PCOS has been chronically underfunded relative to its prevalence - a point reinforced by Dr Melanie Cree, the University of Colorado Anschutz paediatric endocrinologist quoted on the rename, and by Helena Teede's commentary in Time. The argument is that funding bodies, and the specialty silos within which they operate, follow nomenclature. A condition called polycystic ovary syndrome attracts the attention of gynaecology departments; a condition called polyendocrine metabolic ovarian syndrome may attract that of endocrinology, cardiology, metabolic medicine and mental health research. Whether this prediction will be borne out is empirical, but the precedent is suggestive. Patient-side data are striking: the AJMC summary of the consensus reports that 86% of patients and 71% of clinicians surveyed supported the change, citing stigma, confusion and fragmented care as the reasons. These figures are not trivial; they suggest a coalition broader than the academic societies that drove the process.
The dissent: ovarian retention, lost recognition, and the limits of nomenclature
Dissent has been quieter than the consensus, but it exists, and the AKTMLA reader should not assume the rename is uncontested. Three strands deserve attention. The first concerns the retention of the word ovarian. As Stat News reported in its 12 May coverage, the panel was nearly unanimous on PMOS, but a minority voiced dissatisfaction precisely because retaining ovarian in the name forecloses the possibility, suggested by some early research, of a male phenotype of the syndrome. The Scientific American coverage of 12 May made a similar point: the panel itself acknowledged the condition likely affects men, too, yet the name retains the gendered organ. The second concerns the question of lost recognition. Long-standing patient advocates, as reported by Illume Fertility's Dr Ilana Ressler in her summary published in the days after the announcement, have voiced concerns about losing the recognition and visibility that PCOS as a brand has built up over decades — the social media communities, the support groups, the charity funding streams, the language patients use to describe themselves. The Cleveland Clinic and other major institutions are likely to retain parenthetical references to PCOS for years, much as granulomatosis with polyangiitis (Wegener's) continues to appear in print more than a decade after the formal renaming. The third concerns the underlying problem the name was supposed to fix. As the EGOI-PCOS group argued in a January 2026 commentary, the inadequacy of the name reflects a deeper inadequacy in the diagnostic framework itself: the Rotterdam criteria, even as updated in 2023, continue to define the condition in terms that privilege reproductive over metabolic phenotypes, and the diagnostic categories are still organised around morphology, anovulation and hyperandrogenism rather than around insulin resistance. Critics argue that a name change without a criteria change is, at best, a partial reform. The PMOS supporters acknowledge the point and note that the rename is intended to catalyse, not substitute for, that deeper reckoning.
Historical precedents: what disease renaming actually does
Disease renaming is not unprecedented in medicine, and the historical record provides a sobering check on expectations. The clearest analogue is the rename of Wegener's granulomatosis to granulomatosis with polyangiitis, formalised in 2011 by Falk and colleagues in the Journal of the American Society of Nephrology, under the joint endorsement of the American College of Rheumatology, the American Society of Nephrology and the European League Against Rheumatism, and adopted in the 2012 Chapel Hill Consensus Conference nomenclature. The rename was driven partly by revelations of Friedrich Wegener's Nazi-era affiliations and partly by a broader shift from honorific eponyms to disease-descriptive nomenclature. The scientometric analysis by AlRyalat and colleagues, published in Scientometrics in 2018, tracked the diffusion of the new name through the literature from 2010 to 2017: of 2,613 publications using Wegener and 1,443 using GPA over the period, the eponym-only proportion fell year on year to 11.8% by 2014, with hybrid and representative-name terminology dominating thereafter. The lesson is twofold. First, renaming works, but slowly: most current rheumatology textbooks still carry the parenthetical Wegener's a decade and a half after the formal change, and the Cleveland Clinic, StatPearls and Medscape reference entries continue to lead with the new name while preserving the eponym for searchability. Second, even after the new name has taken hold in the literature, clinical conversation, examinations and patient self-description lag for years. Other historical analogues are instructive. Reiter's syndrome was renamed reactive arthritis on closely analogous ethical grounds following the disclosure of Hans Reiter's role in the Third Reich, with the new term now dominant in the literature but the eponym still encountered in older clinical conversation. The 1961 American Academy of Pediatrics decision to replace mongolism with Down syndrome required nearly two decades to take full hold of the lay literature, even though the medical literature converted within five years. Manic-depressive illness, formally replaced by bipolar disorder in DSM-III in 1980, persisted in clinical conversation, popular psychology and patient self-identification into the 2000s. The successive replacement of older psychiatric terminology - neurosis, hysteria, multiple personality disorder, mental retardation - across editions of the DSM and the ICD has consistently produced transition periods of between five and fifteen years during which dual nomenclature confused trainees, examiners and patients alike. There is no reason to expect PMOS to behave differently. The Lancet authors have explicitly factored this lag into their rollout: a three-year transition during which both names will appear in clinical literature, guidelines, ICD-11 and SNOMED CT, with parenthetical references expected to persist for considerably longer. Candidates should regard PCOS and PMOS as effectively synonymous for examination purposes for the foreseeable future, with a slow drift towards PMOS dominance over the late 2020s.
Examination relevance for AKT and MLA candidates
For UK candidates the immediate question is practical. Will the AKT and MLA, in the next two diet cycles, use PCOS, PMOS, or both? At the time of writing the General Medical Council has not issued formal guidance on the question, the MLA content map remains unchanged, and the Royal College of General Practitioners has not yet updated its AKT curriculum statements. Candidates should therefore prepare for both. The defensive position is straightforward: know the condition by both names, recognise that the diagnostic criteria are unchanged, and be prepared to encounter question stems that use either nomenclature, possibly with a parenthetical equivalent. Beyond the terminology itself, the rename creates an examinable opportunity. Candidates may reasonably be asked to identify the multisystem nature of the condition: hyperandrogenism with its dermatological manifestations (hirsutism, acne, female-pattern alopecia), the menstrual and ovulatory dysfunction, the strong association with insulin resistance, type 2 diabetes and metabolic syndrome, the increased cardiovascular risk, the elevated prevalence of obstructive sleep apnoea, and the well-documented increase in anxiety, depression and disordered eating. NICE Clinical Knowledge Summaries on PCOS retain their relevance pending revision: candidates should know first-line investigations (free androgen index, testosterone, sex hormone-binding globulin, fasting glucose or HbA1c, lipid profile, LH:FSH ratio of historical interest, transvaginal ultrasound where indicated), the management of menstrual irregularity with combined hormonal contraception or cyclical progestogens, the role of metformin, the licensed and off-label use of GLP-1 receptor agonists in selected patients with comorbid obesity, and the appropriate use of clomifene, letrozole and gonadotrophins in fertility care. The 2023 International Guideline's emphasis on cardiovascular risk assessment in all affected patients is examinable and frequently underweighted by candidates.
Three further points deserve particular attention. The first concerns insulin resistance. Surveyed clinicians have repeatedly identified insulin resistance as the core pathophysiological feature of the condition, and the AJMC summary of the consensus emphasised that insulin resistance is present even in non-obese phenotypes — a point that has historically been underappreciated in examinations and in clinical practice alike. Candidates should be able to identify the lean phenotype, which by some estimates accounts for around a fifth of affected patients, and to recognise that the absence of obesity does not exclude the diagnosis. The second concerns the four Rotterdam phenotypes (A, B, C and D) defined by combinations of hyperandrogenism, ovulatory dysfunction and polycystic ovarian morphology, with phenotype A carrying the highest metabolic burden and phenotype D, the so-called non-hyperandrogenic phenotype, the lowest. Knowledge of the phenotypic spectrum is a common feature of extended-matching and single-best-answer questions and is unlikely to disappear from the assessment blueprint simply because the umbrella name has changed. The third concerns the adolescent diagnosis, which under the 2023 guideline requires both hyperandrogenism and oligo- or anovulation, with ultrasound and AMH explicitly excluded as criteria in the under-eighteens. Vignettes presenting adolescents with multi-follicular ovaries on incidental imaging remain a high-yield testing ground for the distinction between normal pubertal variation and pathological disease. A working knowledge of disease renaming as a category - the rationale, the precedents, and the predictable lag between formal renaming and clinical adoption - will not directly earn marks, but it will help candidates recognise unfamiliar terminology under examination conditions and respond without paralysis.
Conclusions
The PMOS rename is best understood as neither trivial nor transformative. It is a deliberate, multi-year intervention in the political economy of medical attention, intended to redirect funding, research and clinical conceptualisation away from a narrow reproductive frame and towards the metabolic and endocrine reality that has dominated the scientific literature for two decades. It does not change the diagnostic criteria; it does not resolve the underlying dispute about whether those criteria privilege the right phenotype; and it does not yet command universal assent. For examination candidates, the immediate task is dual-nomenclature literacy and a renewed grasp of the multisystem nature of the condition. For the profession, the deeper task is to decide whether the rename was the first step in a wider rethinking of how endocrine and metabolic disorders are classified, or whether, like several of its predecessors, it will settle into the literature without driving the structural change its proponents intend. The next three years will provide the answer.