PCOS has a new name.
In May 2026, polycystic ovary syndrome (PCOS) was renamed polyendocrine metabolic ovarian syndrome (PMOS).
Same condition. Different acronym. And no, this wasn't a case of somebody deciding we simply didn't have enough medical acronyms to remember.
The old name has been considered misleading for years. You don't need to have polycystic ovaries to have the condition, the so-called “cysts” aren't actually cysts in the traditional sense, and focusing so heavily on the ovaries left out a pretty big part of what the condition actually involves.
So, this PMOS Awareness Month, let's get properly acquainted with PMOS: why the name changed, what symptoms can look like, how it can affect your periods and where to go if you think you might have it.
What does PMOS stand for?
PMOS stands for polyendocrine metabolic ovarian syndrome.
It replaces the name polycystic ovary syndrome (PCOS).
The new terminology was agreed following a huge global consensus process involving people living with the condition, healthcare professionals, researchers and patient organisations.
And each part of the new name tells us something:
- Polyendocrine refers to the multiple hormone systems that can be involved.
- Metabolic recognises the metabolic features of the condition, including insulin resistance.
- Ovarian reflects the role ovarian function can play.
Put them together and you get a much broader description of the condition than “polycystic ovaries.”
Because PMOS was never just about cysts.
Why was PCOS renamed PMOS?
For starters, you don't need ovarian cysts to have PMOS.
Which is quite an inconvenient detail when your condition has spent decades being called polycystic ovary syndrome.
What are often described as “cysts” are actually follicles in the ovaries. And while polycystic ovarian morphology can be one feature of the condition, it isn't something everyone with PMOS has.
The old name also put the ovaries front and centre when PMOS can involve much more than the reproductive system, including hormonal, metabolic and psychological health.
The problem with the name wasn't a new discovery, either. Calls to change it have been around for years.
In 2026, after a global consultation involving 56 professional and patient organisations and thousands of people with lived experience and healthcare professionals around the world, polyendocrine metabolic ovarian syndrome became the new name.
One letter changed.
A much bigger picture emerged.
Is PMOS different from PCOS?
No.
PMOS is the new name for the condition previously known as PCOS.
If you've already been diagnosed with PCOS, the name change doesn't mean your diagnosis has changed or that you suddenly have a different condition.
You may still see PCOS, PMOS or PMOS/PCOS used while healthcare services, research, websites and resources transition to the new terminology.
So don't panic if your old medical letters still say PCOS. They haven't suddenly become vintage documents.
How common is PMOS?
PMOS affects around 1 in 8 women worldwide, making it one of the most common endocrine conditions affecting women of reproductive age.
Despite that, experiences of PMOS can vary enormously.
Some people have mild symptoms. Others have symptoms that significantly affect their everyday lives. And some may have very few noticeable symptoms at all.
There's no single “PMOS period” or one way someone with the condition is supposed to look.
What are the symptoms of PMOS?
PMOS can affect your periods, hair, skin, fertility, metabolism and mental health.
Common symptoms can include:
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Irregular periods or long gaps between periods
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Excess facial or body hair
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Thinning hair or hair loss
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Oily skin and acne
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Weight gain or difficulty losing weight
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Difficulty getting pregnant
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Tiredness
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Darkened, thicker patches of skin, particularly around the neck or armpits
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Depression or anxiety
You might experience several of these, just a few or none noticeably at all.
And because plenty of these symptoms can have other causes, having one or more doesn't automatically mean you have PMOS.
How can PMOS affect your periods?
For some people, irregular or absent periods are one of the first signs that something isn't quite right.
PMOS can affect ovulation, meaning an egg may not be released regularly. That can lead to longer or unpredictable menstrual cycles, irregular periods or periods stopping for stretches of time.
Which can make the question “When was your last period?” considerably harder to answer than healthcare forms seem to anticipate.
Not everyone with PMOS will have irregular periods, though, and your cycle is only one part of the picture.
Can you have PMOS without ovarian cysts?
Yes.
And this is one of the big reasons the name changed.
Having “cysts” was never a requirement for everyone diagnosed with PCOS, despite what the old name strongly suggested.
An ultrasound can sometimes form part of an assessment for PMOS, but diagnosis isn't simply:
cysts = PMOS
no cysts = no PMOS.
The condition is more complex than what can be seen on an ultrasound.
What causes PMOS?
There isn't one single known cause of PMOS.
It's a complex hormonal condition, and genetics are thought to play a role. You're more likely to have PMOS if a close relative has it.
Hormonal and metabolic factors, including insulin resistance and higher levels or activity of hormones called androgens, can also be involved.
And importantly, PMOS isn't something you've caused by doing something “wrong.”
How is PMOS diagnosed?
If you're experiencing symptoms that could be PMOS, your GP is a good place to start.
There isn't one single PMOS test.
A healthcare professional may ask about things like your menstrual cycle and symptoms, and may arrange tests such as blood tests to look at hormone levels and insulin resistance.
Depending on your age and circumstances, an ultrasound may also be used to look at your ovaries.
You may be referred to a specialist such as a gynaecologist or endocrinologist for further assessment.
When should I speak to my GP about PMOS?
Lots of individual PMOS symptoms can happen for all sorts of reasons.
But it's worth speaking to your GP if you think you may have PMOS, particularly if symptoms are affecting your everyday life, work or relationships.
You can also speak to your GP about changes to your periods, including persistent irregularity or long gaps between them.
Before an appointment, it can be useful to make a note of your symptoms and menstrual cycle. If your periods are irregular, don't worry about producing a beautifully colour-coded spreadsheet worthy of an investigation board.
Approximate dates and what you've noticed can still be useful.
Is there treatment for PMOS?
There's currently no cure for PMOS, but there are treatments and lifestyle approaches that can help manage different symptoms.
And because PMOS doesn't look the same for everyone, treatment isn't one-size-fits-all either.
Depending on your symptoms and what matters to you, treatment might focus on things like:
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Regulating periods
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Acne
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Excess hair growth
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Metabolic health
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Fertility
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Mental health and wellbeing
Medicines including hormonal contraception, metformin and treatments for particular symptoms may be considered depending on your individual circumstances.
Your healthcare professional can talk through the options that are appropriate for you.
Can PMOS affect fertility?
It can, but having PMOS doesn't mean you can't get pregnant.
Because PMOS can affect ovulation, some people may find it more difficult to conceive.
There are treatments available to support fertility if needed, so if you're trying to get pregnant and are concerned about your cycle or PMOS, speak to your GP.
Does PMOS affect your health beyond your periods?
Yes, and this is another important part of moving away from the old name.
PMOS can have effects beyond menstruation and fertility.
It can be associated with an increased risk of conditions including type 2 diabetes, high blood pressure and cardiovascular disease. Mental health matters too, with depression and anxiety among the symptoms associated with PMOS.
That doesn't mean everyone with PMOS will develop these conditions.
It does mean that looking after someone with PMOS should involve more than asking about their ovaries.
Where can I find help with PMOS?
If you think you might have PMOS, or you're struggling with symptoms, speak to your GP.
If you already have a diagnosis but your symptoms have changed or your current treatment isn't working for you, you can go back and ask to review your care.
There are also organisations offering information and support for people living with PMOS.
And if you're searching online, don't be surprised if you still find lots of resources filed under PCOS. The terminology changed in 2026, so it'll take a little while for the entire internet to swap its C for an M.
PCOS → PMOS: more than a name change
Changing one letter isn't going to transform the experience of living with PMOS overnight.
But words matter.
Calling the condition polycystic ovary syndrome put decades of emphasis on something that isn't even present in everyone who has it.
Polyendocrine metabolic ovarian syndrome acknowledges something much bigger: a complex condition that can affect hormones, metabolism, ovarian function, periods, skin, hair, fertility and mental health.
So this PMOS Awareness Month, there's a new acronym to remember.
More importantly, there's a bigger picture to understand.
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Our blog is intended to share information and ideas around periods, health, and sustainability. While we do our best to keep content accurate and up to date, things can change over time. The information here is not intended as medical advice — for any health-related concerns, please consult a qualified healthcare professional. For more information on our claims, please see our Claims Page, and for the most up-to-date product information, please visit our Product Pages.
