PCOS: 7.9% or 12.7% of women, depending on the criterion

How many women are affected, and by which criterion

The 2026 meta-analysis is the largest ever conducted on the subject, and its authors themselves rate the certainty of the evidence as very low to low. The gap between 7.9% and 12.7% is not about different populations: it is about whether ovarian morphology is included in the definition. The authors of the 2018 meta-analysis on the same question explicitly called for reducing “inappropriate labelling and the potential psychological harm of an incorrect diagnosis”.

The diagnostic wandering, measured

Gibson-Helm’s international survey (Journal of Clinical Endocrinology and Metabolism, 2017) questioned 1,385 diagnosed women across North America and Europe.

The 15.6% is the harshest figure in the study. Only one woman in six felt she received satisfactory information about her own condition. And the association is strong: being satisfied with the information multiplies by 7 the odds of being satisfied with the diagnostic journey.

One caveat worth stating: recruitment ran through support groups, which probably draws in the hardest journeys. We therefore do not present these figures as the average across all affected women.

One widely circulated figure also needs correcting. This study does not give an “average time to diagnosis” in years. It gives proportions by band. Any figure of the form “on average X years” attributed to this source is misattributed.

What the 2023 guideline changed

The international evidence-based guideline published in 2023 rests on 77 evidence-based recommendations, 54 consensus recommendations and 123 practice points. It changed three concrete things.

The meta-analysis commissioned for the guideline gives AMH a sensitivity of 0.79 and specificity of 0.87 in adults, but only 0.66 and 0.78 in adolescents. And its authors conclude that no international AMH threshold can be recommended. An “AMH cut-off” quoted as a reference therefore does not come from the guideline.

For an adolescent showing signs without meeting criteria, the guideline creates an “increased risk” status, with reassessment no later than eight years after the first period. It is an explicit refusal to label early.

The metabolic risks, and what they are actually worth

Two readings follow. First: the excess risk quoted depends heavily on how diabetes was measured in the study, which should make anyone cautious about an isolated figure. Second: the absolute risk stays moderate, about four cases per thousand woman-years. That is precisely the authors’ argument for screening every one to three years, rather than for alarm.

The relative excess risk is highest in lean women, which contradicts the received idea that the metabolic risk of PCOS comes down to weight.

A useful precision: the 2023 guideline gives no prevalence percentage for metabolic syndrome in PCOS. Figures of that kind in circulation do not come from it.

What is demonstrated, and the real size of the effect

Letrozole is the strongest recommendation in the whole 2023 document: maximal strength, maximal certainty, one of only two to reach that level alongside screening for depression and anxiety. In absolute terms the Cochrane authors translate it as follows: for a 20% chance of live birth on clomiphene, it would be 27% to 35% on letrozole. One methodological detail is worth knowing: this update excluded four trials from the previous version over concerns about data validity, and it is that cleaning of the corpus that lifted the evidence to high certainty.

Conversely, the effect of lifestyle intervention is far more modest than the dominant discourse suggests: 1.68 kg of mean weight loss, and no trial assessed live births, miscarriage or menstrual regularity. The 2023 guideline sets no numerical weight-loss target either, and notes that there are benefits to healthy living even without weight loss.

What is not demonstrated

Inositol. The 2018 Cochrane review gives an odds ratio of 2.42 on live births, but with a confidence interval from 0.75 to 7.83, therefore crossing 1, across two trials and 84 women. The 2023 guideline classifies it as experimental therapy in infertility, and specifies that metformin should be preferred over inositol for hirsutism and central adiposity.

One diet over another. The 2023 guideline is explicit: any dietary composition consistent with general healthy-eating guidance will bring health benefits. It asks that unduly restrictive diets be avoided. On exercise, it notes a lack of evidence that any type or intensity is better than another.

The ketogenic diet. This is a textbook case. The most-cited meta-analysis reports spectacular effects, up to 10.77 kg of weight loss, but these are largely before-and-after comparisons with no control group. In direct comparison with other diets the effect falls to 4.98 kg, with an interval from 0.91 to 9.05. A second independent meta-analysis notes that of ten included studies only three are randomised trials, and that the two trials comparing ketogenic with hypocaloric diets found no significant effect on body weight.

The gluten-free diet. We found neither a randomised trial nor a systematic review on this question in PCOS. There is no evidence base to cite, and any numerical claim on this point has no primary source.

Mental health, the strongest recommendation in the document

Cooney’s meta-analysis (Human Reproduction, 2017), across 30 studies, 3,050 women with PCOS and 3,858 controls, gives an odds ratio of 3.78 for depressive symptoms and 5.62 for anxiety symptoms. For moderate to severe forms, 4.18 and 6.55.

The decisive point: in subgroups matched on body mass index, the association holds, at 3.25 for depression and 6.30 for anxiety. Obesity therefore does not explain the link.

The 2023 guideline turns this into systematic screening for depression in all adults and adolescents, and for anxiety in all adults, at maximal strength and certainty. It acknowledges that the optimal screening interval is not known. Since all the studies are cross-sectional, causation is not established.

A change of name, decided in 2026

A global consensus process bringing together 56 organisations and 14,360 responses from patients and health professionals concluded in 2026 by replacing the term “polycystic ovary syndrome” with “polyendocrine metabolic ovarian syndrome”. The stated reason is explicit: the name is judged inaccurate, it implies pathological ovarian cysts, it obscures the endocrine and metabolic features, and it contributes to diagnostic delay, fragmented care and stigma.

This is a rare event, and it confirms institutionally what the diagnostic-delay figures already suggested: part of the problem lies in the name itself.

In practice, if this concerns you

Two questions decide. On which criteria was the diagnosis made, and was an ultrasound performed in addition to an AMH assay, which the guideline explicitly advises against. And, if you want to conceive, was letrozole offered first line, which is the strongest recommendation in the international document.

Noria Health arranges a full gynaecological and endocrine work-up in Brussels within 24 to 48 hours: cycle assessment, androgen measurements, the 75 g oral glucose tolerance test which remains the most accurate whatever the BMI, and only one of the two modalities between AMH and ultrasound. The report is issued within 24 hours, follow-up is structured at D14, D30 and D90. What Noria Health does not do: stack tests to confirm a label. The same work-up, read against two sets of criteria, gives two different answers, and choosing the criterion is a medical decision that should be explained.

Further reading

• Endometriosis: 190 million women, up to 12 years to diagnosis
• Fibroids: 1 woman in 2 has them without knowing

Sources

1. Neven ACH, Forslund M, Ranasinha S, et al. Prevalence of polycystic ovary syndrome, a global and regional systematic review and meta-analysis. Human Reproduction Update, 2026;32:277-312. https://doi.org/10.1093/humupd/dmaf030
2. Skiba MA, Islam RM, Bell RJ, Davis SR. Understanding variation in prevalence estimates of polycystic ovary syndrome. Human Reproduction Update, 2018;24:694-709. https://doi.org/10.1093/humupd/dmy022
3. March WA, Moore VM, Willson KJ, Phillips DI, Norman RJ, Davies MJ. The prevalence of polycystic ovary syndrome in a community sample assessed under contrasting diagnostic criteria. Human Reproduction, 2010;25:544-551. https://doi.org/10.1093/humrep/dep399
4. Teede HJ, et al. Recommendations from the 2023 international evidence-based guideline for the assessment and management of polycystic ovary syndrome. Human Reproduction, 2023;38:1655-1679. https://doi.org/10.1093/humrep/dead156
5. Gibson-Helm M, Teede H, Dunaif A, Dokras A. Delayed diagnosis and a lack of information associated with dissatisfaction in women with polycystic ovary syndrome. Journal of Clinical Endocrinology and Metabolism, 2017;102:604-612. https://doi.org/10.1210/jc.2016-2963
6. van der Ham K, Laven JSE, Tay CT, Mousa A, Teede H, Louwers YV. Anti-müllerian hormone as a diagnostic biomarker for polycystic ovary syndrome. Fertility and Sterility, 2024;122:727-739. https://doi.org/10.1016/j.fertnstert.2024.05.163
7. Kakoly NS, Khomami MB, Joham AE, et al. Ethnicity, obesity and the prevalence of impaired glucose tolerance and type 2 diabetes in PCOS. Human Reproduction Update, 2018;24:455-467. https://doi.org/10.1093/humupd/dmy007
8. Kakoly NS, Earnest A, Teede HJ, Moran LJ, Joham AE. The impact of obesity on the incidence of type 2 diabetes among women with polycystic ovary syndrome. Diabetes Care, 2019;42:560-567. https://doi.org/10.2337/dc18-1738
9. Legro RS, Brzyski RG, Diamond MP, et al. Letrozole versus clomiphene for infertility in the polycystic ovary syndrome. New England Journal of Medicine, 2014;371:119-129. https://doi.org/10.1056/NEJMoa1313517
10. Franik S, Le QK, Kremer JA, Kiesel L, Farquhar C. Aromatase inhibitors for ovulation induction in infertile women with polycystic ovary syndrome. Cochrane Database of Systematic Reviews, 2022, CD010287. https://doi.org/10.1002/14651858.CD010287.pub4
11. Morley LC, Tang T, Yasmin E, Norman RJ, Balen AH. Insulin-sensitising drugs for women with polycystic ovary syndrome. Cochrane Database of Systematic Reviews, 2017, CD003053. https://doi.org/10.1002/14651858.CD003053.pub6
12. Showell MG, Mackenzie-Proctor R, Jordan V, Hodgson R, Farquhar C. Inositol for subfertile women with polycystic ovary syndrome. Cochrane Database of Systematic Reviews, 2018, CD012378. https://doi.org/10.1002/14651858.CD012378.pub2
13. Lim SS, Hutchison SK, Van Ryswyk E, Norman RJ, Teede HJ, Moran LJ. Lifestyle changes in women with polycystic ovary syndrome. Cochrane Database of Systematic Reviews, 2019, CD007506. https://doi.org/10.1002/14651858.CD007506.pub4
14. Cooney LG, Lee I, Sammel MD, Dokras A. High prevalence of moderate and severe depressive and anxiety symptoms in polycystic ovary syndrome. Human Reproduction, 2017;32:1075-1091. https://doi.org/10.1093/humrep/dex044
15. Teede HJ, et al. Polyendocrine metabolic ovarian syndrome, the new name for polycystic ovary syndrome. The Lancet, 2026;407:2329-2339. https://doi.org/10.1016/S0140-6736(26)00717-8
16. Arsenaki E, Stathi D, Triantafyllidis KK, et al. The effects of ketogenic diet on polycystic ovary syndrome. Clinical Nutrition, 2026;56:106535. https://doi.org/10.1016/j.clnu.2025.11.019

See also: all our articles on gynaecology.

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