The Lancet formally adopted the new name — polyendocrine metabolic ovarian syndrome (PMOS) — in May 2026. Read the Lancet paper →
Reviewed by Julie Boora, Superintendent Pharmacist, TribElle Health Ltd (GPhC Reg. 9012688) · Updated 21 May 2026
Polycystic ovary syndrome (PCOS) — now officially called PMOS — is one of the most misunderstood conditions in women's health. Despite the name, PCOS was never really about having "polycystic" ovaries. Those small fluid-filled sacs seen on ultrasound aren't true cysts at all. They're immature follicles that never developed properly.
The real story? PMOS is driven by hormone imbalances — especially excess androgens (male-type hormones) and insulin resistance. These two factors create a feedback loop that explains why PMOS causes irregular periods, acne, excess hair growth, fertility struggles, and metabolic problems.
Let's break down the science, and the latest evidence, so you can see what's really happening in your body and why.
Myth-busting the name: PMOS isn't about cysts
The Lancet rename formally validates something clinicians and patients have long known. PMOS is now the global standard term. Here's why the old name was misleading:
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In PMOS, the ovaries contain many small follicles (undeveloped eggs)
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They look like "cysts" on ultrasound, but they're not dangerous or cancerous
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These follicles build up because ovulation doesn't occur regularly
Key point: The ovaries look "polycystic" because of hormone disruption — not the other way around.
Core driver 1: excess androgens
One of the defining features of PMOS is hyperandrogenism — higher-than-normal levels of hormones like testosterone and androstenedione.
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Androgens disrupt follicle maturation — no dominant egg develops
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No ovulation = irregular or missed periods
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High androgen levels also cause acne, hirsutism (excessive facial or body hair), and scalp hair thinning
Ovarian theca cells (the hormone-producing cells around follicles) are unusually sensitive in PMOS, producing excess androgens even in response to normal signals. NHS: PMOS symptoms and causes
Core driver 2: insulin resistance
Here's where PMOS goes beyond reproductive health into metabolism.
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Insulin resistance means cells don't respond properly to insulin
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To compensate, the body makes more insulin (hyperinsulinemia)
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High insulin stimulates the ovaries to produce more androgens
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High insulin lowers SHBG (sex hormone binding globulin) → more free testosterone circulates in the blood
Key point: PMOS can affect women of all body types. Many lean women also have insulin resistance — although it's more common and more severe in those who are overweight.
The PMOS rename specifically exists to foreground these metabolic dimensions. Because PMOS affects multiple systems, its impact goes well beyond the ovaries.
Metabolic health
1 in 8 women with PMOS has insulin resistance. Over half will develop prediabetes or type 2 diabetes by age 40.
Heart health
Higher rates of cholesterol problems, high blood pressure, and metabolic syndrome.
Endometrial cancer risk
Irregular ovulation means unopposed oestrogen, which can cause endometrial thickening over time.
Mental health
Higher rates of anxiety and depression, often linked to symptoms like weight changes, infertility, and hirsutism.
The 2013 Endocrine Society Guideline is now retired. In 2023, a new International Evidence-Based PCOS Guideline was released, endorsed by the Endocrine Society, ASRM, ESHRE, and others.
Key updates from the 2023 guideline
Diagnosis now requires two of three:
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Clinical or biochemical androgen excess
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Ovulatory dysfunction
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Polycystic ovaries on ultrasound or elevated AMH levels (in adults, AMH can replace ultrasound)
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The guideline recognises PMOS as a lifelong condition with metabolic, reproductive, and psychological implications
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Care should include screening for metabolic and mental health risks, lifestyle support, and shared decision-making
2026 update: PCOS is now PMOS
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Polycystic Ovary Syndrome (PCOS) has been renamed Polyendocrine Metabolic Ovarian Syndrome (PMOS) following international expert consensus
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The name change reflects that the condition is not just a reproductive disorder, but a complex condition affecting multiple body systems
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The new name better reflects links to hormonal imbalance, insulin resistance, metabolic health, cardiovascular risk, and mental wellbeing
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PMOS is a lifelong endocrine and metabolic condition — not simply a reproductive syndrome
PMOS (polyendocrine metabolic ovarian syndrome) is the new name for what was previously called PCOS. It was formally adopted in The Lancet in May 2026. Same condition, updated name that better reflects its complexity.
The old name implied the presence of ovarian cysts, which is inaccurate. PMOS reflects that it is a complex polyendocrine and metabolic condition — not primarily a gynaecological one. The rename aims to improve diagnosis, public understanding, and whole-body care for women.
Yes — same condition, new name. All previous PCOS diagnosis, research, and treatment guidance applies to PMOS. If you have a PCOS diagnosis, nothing about your condition or treatment changes.
No. What appear as cysts on ultrasound are actually arrested follicles — immature eggs that didn't develop fully. PMOS is driven by hormone imbalances and insulin resistance, not ovarian cysts. Many women with PMOS don't have the appearance of "polycystic" ovaries at all.
Final word from TribElle
PMOS is common, complex, and often misunderstood. By breaking the silence and explaining the science, we can give women clarity and confidence. Your symptoms are not your fault.
With the right support — clinical care, nutrition, and sometimes medication — PMOS is manageable, and your health and goals are still within reach. The renaming is a validation of what women have long known: this condition was always bigger than its name suggested.