Updated October 2026: PCOS has a new name. In May 2026, polycystic ovary syndrome was officially renamed polyendocrine metabolic ovarian syndrome, or PMOS (here's everything you need to know about the name change). We've updated this guide to reflect it, plus newer research on how PMOS affects the whole body, including its links with histamine, inflammation and neurodivergence.
PMOS is one of the most common hormonal conditions affecting people with ovaries. It's estimated to affect around 1 in 8 women and people with ovaries, which is more than 170 million people worldwide, and many remain undiagnosed. For some, symptoms are mild. For others, PMOS can have a big impact on physical health, mental wellbeing and quality of life.
If you're trying to understand PMOS, whether for yourself or someone you care about, it's okay to take this information slowly. It's complex, and your experience is valid even if it doesn't look like someone else's.
Why has PCOS been renamed PMOS?
The short version: the old name centred ovarian "cysts" that many people don't actually have, and kept the focus on periods and fertility. The new name, agreed through a 14-year global process and published in The Lancet in May 2026, reflects that this is a whole-body hormonal and metabolic condition. You'll still see "PCOS" on NHS pages and in GP notes for a while, as there's a three-year transition, but both names mean the same condition.
For the full story behind the name change, what each part of the new name means and what it means for you, read our guide: PCOS just got rewritten: understanding PMOS without the confusion.
What is PMOS?
PMOS is a whole-body hormonal and metabolic condition. People with PMOS often have higher levels of androgens, which are hormones present in all bodies but typically higher in people assigned male at birth. Many also have insulin resistance, where the body needs more insulin to keep blood sugar steady.
These two often feed into each other. Higher insulin can push the ovaries to make more androgens, and higher androgens can make insulin resistance worse. This can interfere with ovulation, but it also affects skin, hair, weight, mood, sleep, energy, and long-term heart health. Which is why PMOS is really not "just" a period problem.
More than a menstrual health condition
For years, PCOS was mostly treated as a gynae or fertility issue. The research now paints a much bigger picture. PMOS is linked with:
- Metabolic health: insulin resistance and a higher risk of type 2 diabetes, gestational diabetes and fatty liver disease, in people of all body sizes.
- Heart health: higher rates of high blood pressure and cholesterol changes, which can raise the risk of heart disease and stroke later in life.
- Mental health: a UK study of nearly 17,000 women with PCOS found significantly higher rates of depression, anxiety, bipolar disorder and eating disorders.
- Sleep: more sleep disruption and a higher risk of obstructive sleep apnoea.
- Skin and hair: acne, excess facial or body hair, and thinning hair on the scalp, mostly driven by androgens.
- Inflammation and the immune system: PMOS is associated with chronic low-grade inflammation across the body (more on this below).
- Reproductive health: irregular or absent ovulation and periods, and a higher risk of the womb lining thickening if periods are very infrequent.
Common symptoms of PMOS
PMOS presents differently from person to person. Common symptoms include irregular periods, missed periods, or no periods at all. Some people experience acne, excess facial or body hair, or thinning hair on the scalp. Weight changes can happen, though PMOS affects people of all body sizes.
Other symptoms can include fatigue, sleep disruption, pelvic pain, headaches, brain fog and changes in mood. Not everyone with PMOS has all of these, and some people have very few outward signs at all.
PMOS, inflammation and histamine
Histamine comes up a lot in PMOS conversations online, so let's look at what the science actually says right now.
What we know: PMOS is associated with chronic low-grade inflammation. A 2024 review in Frontiers in Immunology found people with PMOS tend to have higher levels of inflammatory markers and more immune cells in fat tissue, including mast cells, the immune cells that store and release histamine. Inflammation seems to interact with insulin resistance and high androgens, with each one making the others worse.
We also know sex hormones and histamine talk to each other. Oestrogen can prompt mast cells to release histamine, and histamine may in turn influence hormone production in the ovaries. This is one reason some people notice histamine-type symptoms (flushing, hives, headaches, a blocked nose, gut issues) shifting across their cycle.
What we don't know yet: there's very little research looking directly at histamine intolerance or mast cell activation in people with PMOS. A lot of what you'll read online comes from personal experience or wellness brands rather than studies. If you notice histamine-type symptoms, they're worth tracking and raising with your GP, but be wary of anyone selling a guaranteed "histamine fix" for PMOS.
PMOS and neurodivergence
This is one of the most interesting areas of newer research. If you're autistic, ADHD or otherwise neurodivergent and have PMOS, you're not imagining the overlap.
- Autism: a large UK study in Translational Psychiatry (2018) found autistic women were around twice as likely to have PCOS as non-autistic women, and women with PCOS were around twice as likely to have an autism diagnosis.
- Hormone-related symptoms: a 2014 study in Molecular Autism found autistic women were more likely to report hormone-linked symptoms such as irregular periods, painful periods and severe acne.
- ADHD: a smaller 2015 study found women with PCOS reported more ADHD symptoms, both now and in childhood, than women without it. More research is needed, especially for adults diagnosed later in life.
- The next generation: a 2026 meta-analysis in BMC Psychiatry, covering almost 1.4 million mother and child pairs, found children of mothers with PMOS had around 40% higher odds of ADHD. Earlier reviews have found similar links with autism.
Why might this be? Researchers think hormones, especially androgen levels before birth, may play a role in brain development, and shared genetics are likely part of it too. These studies show a link, not that one causes the other.
The practical side matters just as much. Being neurodivergent can make PMOS harder to live with and harder to get diagnosed. Sensory sensitivities can make acne treatments, hair removal or some medications feel unbearable. Differences in interoception (sensing what's going on inside your body) can make symptoms harder to notice or describe. Executive function can make medication routines and symptom tracking feel like a lot. And many neurodivergent people are already used to being dismissed in healthcare settings. You deserve care that adapts to you, not the other way round.
Diagnosis and delays
There's no single test for PMOS. In adults, diagnosis usually means having two of these three:
- Irregular or absent ovulation, often showing up as irregular periods
- Higher androgen levels on a blood test, or androgen-related symptoms like excess hair growth or acne
- Polycystic-appearing ovaries on ultrasound, or a raised AMH blood test
Other conditions, such as thyroid issues, should be ruled out first. With the new research showing cysts aren't actually part of the condition, guidance on using ultrasound may change in the 2028 guideline update.
Many people live with symptoms for years before getting a diagnosis, often feeling dismissed or told their concerns aren't serious enough. Delayed diagnosis is common and can be emotionally draining. Feeling frustrated or unheard is a valid response.
PMOS and fertility
PMOS can affect ovulation, which may make conception more difficult for some people. However, many people with PMOS conceive naturally. Others conceive with medical support such as ovulation-inducing medication.
A PMOS diagnosis doesn't equal infertility. Equally, not everyone with PMOS wants children, and choosing not to pursue pregnancy is just as valid. Your health matters regardless of your reproductive plans, which is exactly what the new name is trying to reflect.
Management and treatment
There's no cure for PMOS, but symptoms can be managed. Treatment is individual and may include hormonal contraception, medication to support ovulation, treatment for insulin resistance such as metformin, or symptom-specific support such as acne treatment.
Because PMOS is a whole-body condition, good care should look at the whole body too. That can include regular checks of blood pressure, blood sugar and cholesterol, support with sleep, and mental health support, not just your periods.
Management isn't about achieving a particular weight or lifestyle ideal. It's about supporting health, comfort and autonomy.
Emotional wellbeing and PMOS
Living with PMOS can affect self-esteem, body image and mental health. Anxiety and depression are more common among people with PMOS, particularly when symptoms are dismissed or misunderstood.
Support can make a meaningful difference. You deserve care that takes both physical and emotional wellbeing seriously, and if you're neurodivergent, care that's neuro-affirming too.
You may find it helpful to explore trusted organisations and charities offering PMOS-specific information and peer support. You can find these collected on our support links page, which brings together charities and resources for PMOS and related conditions.
FAQs
Is PCOS the same as PMOS?
Yes. PMOS (polyendocrine metabolic ovarian syndrome) is the new name for PCOS, announced in May 2026. It's the same condition with a more accurate name. Read more about the name change.
How common is PMOS?
PMOS affects around 1 in 8 women and people with ovaries worldwide, more than 170 million people, though many remain undiagnosed.
Does PMOS always involve cysts?
No. The so-called cysts are immature follicles, and new research found no increase in abnormal ovarian cysts in people with the condition. It's a big part of why the name changed.
Is PMOS just a period problem?
No. It affects multiple hormone systems, metabolism, heart health, skin, sleep and mental health, as well as periods and ovulation.
Is PMOS linked to ADHD or autism?
Research shows a link. Autistic women are more likely to have PMOS, women with PMOS are more likely to be autistic or report ADHD symptoms, and children of mothers with PMOS have higher rates of ADHD and autism. Hormones and shared genetics are both thought to play a part.
Can PMOS be cured?
There's no cure, but symptoms can often be managed effectively with personalised care.
Does PMOS only affect people who want children?
No. PMOS affects many aspects of health beyond fertility, regardless of reproductive goals.
References
-
Teede H et al. (2026) Polyendocrine metabolic ovarian syndrome: the new name for polycystic ovary syndrome. A multistep global consensus process. The Lancet
https://www.endocrine.org/news-and-advocacy/news-room/2026/pcos-name-change -
ESHRE: PCOS is renamed following unprecedented international consensus
https://www.focusonreproduction.eu/news-and-activities/pcos-is-renamed-following-unprecedented-international-consensus/ -
Berni TR et al. (2018) Polycystic ovary syndrome is associated with adverse mental health and neurodevelopmental outcomes. Journal of Clinical Endocrinology & Metabolism
https://academic.oup.com/jcem/article/103/6/2116/4964634 -
Cherskov A et al. (2018) Polycystic ovary syndrome and autism: a test of the prenatal sex steroid theory. Translational Psychiatry
https://research-information.bris.ac.uk/en/publications/polycystic-ovary-syndrome-and-autism-a-test-of-the-prenatal-sex-s/ -
Pohl A et al. (2014) Uncovering steroidopathy in women with autism: a latent class analysis. Molecular Autism
https://neuroscience.cam.ac.uk/publications/uncovering-steroidopathy-in-women-with-autism-a-latent-class-analysis -
(2015) Attention deficit-hyperactivity disorder symptoms in women with polycystic ovary syndrome. International Journal of Psychiatry in Medicine
https://acikerisim.erbakan.edu.tr/items/23b9e669-b44e-4d75-ac3a-e7dbc1a67efd -
Cao Q et al. (2026) Neuropsychiatric disorders in children of mothers with polycystic ovary syndrome: a systematic review and meta-analysis. BMC Psychiatry
https://link.springer.com/article/10.1186/s12888-026-08047-4 -
Deng H et al. (2024) Systematic low-grade chronic inflammation and intrinsic mechanisms in polycystic ovary syndrome. Frontiers in Immunology
https://doi.org/10.3389/fimmu.2024.1470283 -
Zierau O et al. (2012) Role of female sex hormones, estradiol and progesterone, in mast cell behavior. Frontiers in Immunology
https://www.frontiersin.org/articles/10.3389/fimmu.2012.00169/full -
NHS: Polycystic ovary syndrome (PCOS)
https://www.nhs.uk/conditions/polycystic-ovary-syndrome-pcos/ -
World Health Organization: Infertility fact sheet
https://www.who.int/news-room/fact-sheets/detail/infertility -
Endocrine Society: Clinical practice guidelines
https://www.endocrine.org/clinical-practice-guidelines -
Office on Women's Health (U.S. Dept of Health & Human Services): PCOS information
https://www.womenshealth.gov/a-z-topics/polycystic-ovary-syndrome
Support and charities
-
Verity: the UK PCOS/PMOS charity
https://www.verity-pcos.org.uk/ -
Monash University: evidence-based PCOS lifestyle and care resources
https://www.monash.edu/medicine/pcos -
Fertility Network UK: PCOS support
https://fertilitynetworkuk.org/pcos/ -
PCOS Awareness Association: patient resources
https://www.pcosaa.org/
