What exactly is PCOS?

PCOS is one of the most common syndromes among women, and one of the most poorly understood. It affects 170 million people worldwide of reproductive age. Its symptoms vary, which makes diagnosis difficult: irregular or absent periods, persistent acne, excess body hair, weight gain, sometimes infertility.

What is less visible, but equally important: an increased risk of diabetes, hypertension, cardiovascular disease, and a significant impact on mental health (anxiety, depression, eating disorders).

The problem: a name that misleads

The word polycystic suggests that ovaries contain cysts. That is what most patients believe when they receive their diagnosis. That is also what many doctors continue to think.

In reality, these are not cysts. What ultrasound reveals are small follicles (normal ovarian structures) that have stopped midway through their development. Not cysts in the medical sense. The mistake dates back to another era, before ultrasound even existed.

The result, in numbers

A misleading name has real-world consequences: up to 70% of women with the condition remain undiagnosed. Many believe the syndrome only affects their ovaries. And the stigma tied to fertility remains heavy, particularly in cultures where having children is central.

The new name: PMOS

After two global surveys totalling 14,360 responses and two consensus workshops, the agreed name is polyendocrine metabolic ovarian syndrome (PMOS).

Three words, three realities of the syndrome:

• Polyendocrine, several hormones are dysregulated at once, not only those from the ovaries.
• Metabolic, insulin resistance, increased risk of diabetes and cardiovascular disease.
• Ovarian, the ovaries are indeed involved, but as part of a system, not as the sole origin.

What does this mean for patients?

Nothing changes immediately. A diagnosis made yesterday remains valid. Treatments are not modified. Diagnostic criteria are not modified either.

What does change is what comes next. Over three years, the new name will enter electronic medical records, WHO international classifications, medical textbooks and patient-facing websites. The goal is concrete: diagnose earlier, explain better, treat better, reduce the shame associated with the word.

Why polycystic is medically wrong

The term originates from a time when round structures covering ovaries were observed at autopsy or during surgery and interpreted as cysts. Ultrasound has since shown a different reality: these structures are antral follicles arrested in maturation. They are not pathological cysts in the sense used for functional or dermoid ovarian cysts.

Three major clinical consequences

1. Massive diagnostic delay. Up to 70% of affected patients are never diagnosed. For those who are, the average delay from first symptoms to diagnosis often exceeds several years. The name contributes to this: primary-care physicians and patients think of an isolated ovarian problem and fail to connect it to metabolic, dermatological or psychological signs.

2. A reductive framing. PCOS is multisystemic. It combines, to varying degrees:

• endocrine disturbances (hyperandrogenism, central hormonal dysregulation),
• metabolic disturbances (insulin resistance in 85% of patients, increased risk of type 2 diabetes, dyslipidaemia, hepatic steatosis, hypertension),
• reproductive disorders (oligo-anovulation, infertility, pregnancy complications),
• dermatological manifestations (acne, hirsutism, alopecia),
• psychological consequences (depression, anxiety, eating disorders).

Focusing attention on the ovary means obscuring four-fifths of the clinical picture.

3. Sustained stigmatisation. In some cultures, the association of the diagnosis with fertility and reproductive organs adds a considerable social burden. In the surveys, avoiding stigma was the highest-priority principle for patients, ahead of strict scientific precision.

How do you rename a globally recognised syndrome

Renaming a globally recognised syndrome does not happen by signing a petition. The initiative, led by Helena Teede (Monash University), mobilised:

• 56 organisations across academia, clinical practice and patient advocacy,
• Two global Delphi surveys, 14,360 cumulative responses (10,411 patients, 3,949 health professionals),
• Two consensus workshops (November 2025 and February 2026) using Nominal Group Technique,
• An independent marketing analysis to assess the transition.

The workshops used the James Lind Alliance methodology, with patient-clinician co-chairs in each subgroup. The result: near-unanimous support for the change, and a name selected after several iterations.

Why precisely polyendocrine metabolic ovarian

Several candidates were shortlisted. One was dropped along the way: endocrine metabolic ovulatory syndrome, whose acronym EMOS overlapped with a youth subculture carrying problematic emotional connotations. Another, metabolic endocrine reproductive syndrome, formed the same acronym as Middle East Respiratory Syndrome (MERS).

Three-year transition

The implementation plan, co-designed with implementation-science experts, includes eight steps: academic publication, multilingual resources, integration into electronic medical records, alignment with WHO for the ICD, and update of the International Guidelines in 2028. All over three years, with continuous evaluation.

For patients, nothing urgent changes. The diagnostic criteria (revised Rotterdam 2023: oligo-anovulation, clinical or biochemical hyperandrogenism, polycystic ovaries on ultrasound or elevated AMH) remain those used since the 2023 International Guideline. Treatments too.

What changes progressively is the medical, social and institutional recognition of a reality the name had been hiding. And that is exactly the goal: better screening, better understanding by patients themselves, less shame.

Methodology: modified Delphi and Nominal Group Technique

The process combines four methods, aligned with James Lind Alliance standards:

1. Two global Delphi surveys (April-October 2025 and January 2026), preceded by two earlier surveys (2017 and 2023) that had measured patient mandate for change. Cumulative total: 22,068 responses.
2. Stratified purposive sampling with availability in five languages (English, Chinese, German, Persian, Malay) across three platforms (Qualtrics, Google Forms, WeChat).
3. Two Nominal Group Technique workshops (November 2025, February 2026) with WHO-region representation, patient-clinician co-chairs in each subgroup, and independent observers enforcing the code of conduct.
4. Pro bono marketing analysis by a global agency (including an AI module) to assess feasibility, clarity, and transition strategies.

Survey A gathered 9,358 patient responses and 3,656 clinician responses. Survey B (re-contact of consenting participants) returned 1,053 patient and 293 clinician responses (49% response rate). Workshops brought together 27 patients and 63 clinicians, with representation across key disciplines: obstetrics-gynaecology, reproductive endocrinology, general endocrinology, general practice, nutrition, paediatrics, dermatology, psychology.

Pathophysiology: why polyendocrine is more accurate than polycystic

Recent multi-ancestry pan-genomic analyses (Zhao et al., Nat Genet 2025) confirm the polygenic origin of the syndrome, with converging signals across neuroendocrine, metabolic and reproductive pathways.

Central neuroendocrine abnormalities. Increased pulsatility of hypothalamic GnRH leads to chronic LH elevation and disrupted ovarian steroidogenesis. This central dysregulation precedes and amplifies peripheral hyperandrogenism.

Hyperandrogenism and insulin resistance. Insulin resistance is present in 85% of patients, including 75% of lean patients (BMI ≤ 25 kg/m²). Compensatory hyperinsulinaemia stimulates androgen production by ovarian theca cells and, frequently, by the adrenals. This dual central and peripheral mechanism explains why androgenisation can persist independently of body composition.

Ovarian dysfunction. Hyperinsulinaemia disrupts granulosa and theca cells, worsening local hyperandrogenism. AMH is elevated due to disordered folliculogenesis, justifying its integration into adult diagnostic criteria (International Guideline 2023). Antral follicles accumulate without complete maturation. That is the ultrasound image historically mislabelled polycystic.

Cardiometabolic risk: the long-minimised dimension

Tay et al.'s systematic review (2024), integrated into the Lancet argument, documents, across mostly premenopausal cohorts:

Added to this: increased type 2 diabetes, metabolic-associated steatotic liver disease (MASLD), dyslipidaemia, gestational diabetes, and obstetric complications documented in Bahri Khomami et al.'s meta-analyses (2024, Nature Communications). Including metabolic in the new name is therefore clinically and epidemiologically justified.

Terminology selection process

Survey A assessed support for different approaches:

• New symptomatic name: 86% of patients, 71% of clinicians.
• Generic name (asthma-style): 45% and 54%.
• Keep PCOS acronym with new wording: 20% and 40%.

For descriptors, Survey A validated: endocrine (85%), polyendocrine (81%), metabolic (76%), ovulatory (54%), reproductive (54%). Workshop A initially ranked endocrine metabolic ovulatory syndrome first, until the EMOS brand was deemed problematic. Survey B confirmed polyendocrine metabolic ovulatory syndrome in the lead (66%), before Workshop B substituted ovarian for ovulatory (70% support) to capture ovarian, follicular and ovulatory disorders, and to remain relevant after menopause.

Out of 90 workshop participants, only two opposed the name change. The patient mandate has been overwhelming and consistent since 2017.

Eight-step implementation strategy

The plan, anchored in the Consolidated Framework for Implementation Research and Expert Recommendations for Implementing Change, articulates:

1. Academic publication and dissemination (commentaries, editorials, textbooks).
2. Co-design of multilingual patient and professional resources.
3. Coordinated global communication with learned societies.
4. Integration into electronic medical records and SNOMED-CT.
5. Alignment with governments, funders, journals, pharmaceutical industry.
6. Formal engagement with WHO for the ICD.
7. Managed three-year transition with ongoing evaluation.
8. Integration into the 2028 update of the International Guidelines (195 countries).

Implications for clinical practice

Three short- and medium-term consequences to expect:

1. Pressure on national guidelines: the 2028 update of the International Guideline will serve as the official tipping point. National learned societies must settle terminology by then.
2. Recalibration of screening: if the new name does its job, more patients will be referred for a full metabolic workup at first suspicion, rather than for an isolated gynaecological consultation.
3. Patient communication: a transitional period when the term PCOS will continue to be used. Clinical communication will need to anticipate potential confusion (has my syndrome changed?).

For researchers and clinicians, the moment is also one of consistency in publications: adopting the new nomenclature now (with a transitional mention of the old) speeds up uptake and improves future bibliographic traceability.

Teede HJ, Bahri Khomami M, Morman R, Laven JSE, Joham AE, Costello MF, Patil M, Rees DA, Berry L, Cree MG, Zhao H, Norman RJ, Dokras A, Piltonen T, on behalf of the Global Name Change Consortium. Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome: a multistep global consensus process. Lancet. 2026 May 12. doi:10.1016/S0140-6736(26)00717-8. Open Access (CC BY 4.0).