Polyendocrine Metabolic Ovarian Syndrome (PMOS): Previously Called PCOS

What irregular periods, acne, excess hair, fertility and metabolic health have in common

If you have previously been told you have polycystic ovary syndrome, or PCOS, you may now start seeing a different name for the condition.

In May 2026, PCOS was renamed polyendocrine metabolic ovarian syndrome, or PMOS.

The condition itself has not suddenly changed.

The new name reflects something important: this is not simply a problem of ovarian cysts.

PMOS can affect:

• periods and ovulation
• hormones
• acne and hair growth
• fertility
• weight and metabolism
• diabetes risk
• emotional wellbeing.

And despite the old name, you do not need to have ovarian cysts to have it.

For now, many people — and many medical records — will still use the familiar term PCOS.

This guide mainly uses the new term PMOS, while also referring to PCOS where helpful because that remains the name many people recognise.

What actually is PMOS?

PMOS is a common, long-term hormonal and metabolic condition.

PMOS affects around one in eight women, although many remain undiagnosed.

The underlying biology varies from person to person.

Common features include:

• irregular or absent ovulation
• higher androgen activity
• insulin resistance
• changes in ovarian follicles
• metabolic changes.

Androgens are hormones such as testosterone. Everyone produces them, but increased androgen activity can contribute to acne, excess facial or body hair and sometimes scalp hair thinning.

Insulin resistance means the body needs more insulin than usual to keep blood glucose under control. It is common in PMOS and is one reason the condition matters beyond periods and fertility.

Why was the name PCOS changed?

The old name has caused confusion for years.

“Polycystic ovary syndrome” makes it sound as though the condition is mainly caused by ovarian cysts.

It isn’t.

What can appear on ultrasound are usually multiple small immature follicles, not the type of ovarian cyst that might rupture or require surgery.

Some people with PMOS have this ovarian appearance.

Others do not.

And people without PMOS can sometimes have ovaries that look “polycystic” on ultrasound.

The new name — polyendocrine metabolic ovarian syndrome — reflects the broader hormonal, metabolic, reproductive and psychological effects of the condition.

What symptoms can PMOS cause?

The pattern varies enormously.

Some people mainly notice irregular periods.

Others first seek help because of acne, facial hair or difficulty becoming pregnant.

Common features include:

• irregular periods
• very widely spaced periods
• periods stopping for months
• difficulty predicting ovulation
• acne
• increased facial or body hair
• scalp hair thinning
• difficulty becoming pregnant
• weight gain or difficulty managing weight
• darker thickened skin in some areas
• mood symptoms or reduced quality of life.

You do not need to have all of these symptoms.

And body size does not determine whether someone can have PMOS. The condition occurs across the weight spectrum.

Does irregular periods automatically mean PMOS?

No.

PMOS is common, but irregular periods can have many other causes.

These include:

• pregnancy
• thyroid disease
• raised prolactin
• significant weight change
• intensive exercise
• undernutrition
• perimenopause
• some medicines
• other hormonal conditions.

Certain less common endocrine disorders can also mimic PMOS.

That is why diagnosis involves more than simply noticing irregular cycles or ordering an ultrasound.

How is PMOS diagnosed?

In adults, diagnosis is based on a combination of characteristic features after other important causes have been excluded.

The current international evidence-based guideline uses three main features:

1. irregular or absent ovulation, usually reflected by irregular menstrual cycles
2. clinical or biochemical evidence of increased androgen activity, such as excess hair growth or elevated androgen levels on blood tests
3. polycystic ovarian morphology, assessed by ultrasound or, in appropriate adults, anti-Müllerian hormone testing.

Generally, two of these three features are required.

But there is an important shortcut:

If you already have irregular menstrual cycles and clear evidence of increased androgen activity, you usually do not need an ovarian ultrasound or AMH test simply to confirm the diagnosis.

That can save unnecessary testing.

So I don’t necessarily need an ultrasound?

Correct.

This is a common misconception.

Many patients are told:

“Your ultrasound was normal, so you don’t have PCOS.”

or:

“Your ovaries look polycystic, so you must have PCOS.”

Neither statement is necessarily correct.

Ultrasound is only one possible part of the diagnostic picture.

If irregular ovulation and androgen excess are already present, imaging may add little to the diagnosis.

What about AMH testing?

Anti-Müllerian hormone, or AMH, can now be used instead of ultrasound to identify polycystic ovarian morphology in some adults.

But AMH is not a stand-alone test for PMOS.

A high AMH result by itself does not diagnose the condition.

And ordering AMH simply because someone has acne or irregular periods can create more confusion than clarity.

Is diagnosis different in teenagers?

Yes.

Irregular periods and acne are both common during normal puberty, which makes overdiagnosis a real risk.

In adolescents, current guidance requires both:

• persistent menstrual irregularity defined according to time since the first period
• clinical or biochemical hyperandrogenism

after excluding other explanations.

Ultrasound and AMH should not be used to diagnose PMOS in adolescents.

Someone who has only one feature may be considered “at risk” and reviewed over time rather than being given a premature diagnosis.

Why do periods matter beyond fertility?

If ovulation occurs very infrequently, the lining of the uterus may be exposed to oestrogen for long periods without enough progesterone.

Over many years, this can increase the risk of endometrial hyperplasia and endometrial cancer.

The absolute risk for an individual remains low, but going many months repeatedly without a period should not simply be ignored.

Treatment may therefore be recommended to protect the uterine lining even if becoming pregnant is not currently a priority.

Does PMOS mean I will become infertile?

No.

PMOS is an important cause of difficulty with ovulation, but infertility is not inevitable.

Many women with PMOS become pregnant naturally.

Others need help to restore or induce ovulation.

If fertility treatment is needed, current international guidance recommends letrozole as the preferred first-line medicine for inducing ovulation in women with PMOS who are not ovulating and have no other major infertility factor.

The important message is:

PMOS may make getting pregnant harder, but it does not mean you cannot have children.

If I don’t want a baby now, why does the diagnosis matter?

Because fertility is only one part of PMOS.

Long-term care also involves thinking about:

• menstrual health
• diabetes risk
• blood pressure
• cholesterol
• sleep
• mental health
• body image
• cardiovascular risk factors.

The modern approach deliberately treats PMOS as a lifelong health condition, not simply a fertility disorder.

What health checks should I have?

Your exact follow-up should be individualised, but PMOS is a good reason to periodically review metabolic health.

This may include:

• blood pressure
• glucose or diabetes testing
• cholesterol and other blood lipids
• weight or waist measures when clinically useful
• smoking
• sleep symptoms
• mental health.

Current international guidance recommends assessment of cardiovascular risk factors and glycaemic status in people with PMOS regardless of body size.

The point is risk awareness, not assuming that someone with PMOS will inevitably develop diabetes or heart disease.

Why does diabetes come up so often?

Insulin resistance is common in PMOS.

Over time, this can increase the likelihood of:

• impaired glucose tolerance
• gestational diabetes
• type 2 diabetes.

Risk is influenced by many things, including age, family history, body composition, activity and ethnicity.

This is one reason metabolic health deserves attention even when periods or fertility are not causing problems.

Does PMOS cause weight gain?

The relationship is more complicated than that.

PMOS can make weight management harder for some people because of metabolic, hormonal and appetite-related factors.

But weight does not cause every case of PMOS, and telling someone simply to “lose weight and everything will fix itself” is neither accurate nor particularly useful.

Current guidance emphasises healthy lifestyle behaviours for everyone with PMOS, including people who are not overweight.

Benefits can occur even without weight loss.

What lifestyle changes actually help?

There is no single special “PCOS diet”.

The best eating pattern is one that:

• is nutritionally balanced
• can be maintained
• supports metabolic health
• fits your preferences, culture and lifestyle.

No one specific dietary composition has been shown to be universally superior for PMOS.

Regular physical activity is also important, including both aerobic exercise and resistance training.

The goal is broader than weight loss.

It is to improve:

• insulin sensitivity
• cardiovascular fitness
• muscle
• sleep
• mood
• long-term metabolic health.

What treatment can help irregular periods?

Treatment depends partly on whether pregnancy is currently wanted.

If pregnancy is not the goal, the combined oral contraceptive pill is commonly used to:

• regulate bleeding
• reduce androgen-related symptoms
• protect the uterine lining.

Other hormonal approaches may be appropriate when the combined pill is unsuitable.

The right choice depends on your medical history, contraception needs, bleeding pattern and preferences.

What can help acne or excess facial hair?

Options may include:

• the combined oral contraceptive pill
• standard acne treatments
• cosmetic hair-removal methods
• laser or light-based hair reduction
• selected anti-androgen medicines.

Hair growth responds slowly.

Medication may take months, not weeks, before the benefit becomes obvious.

Some anti-androgen medicines can harm a developing male fetus, so reliable contraception is important when they are used in someone who could become pregnant.

Where does metformin fit?

Metformin improves insulin sensitivity and is widely used in PMOS, particularly when metabolic health is a concern.

Depending on the individual, it may help with:

• insulin resistance
• glucose metabolism
• some menstrual irregularity
• metabolic risk factors.

It is not simply a “fertility drug”, and it is not automatically required for everyone with PMOS.

Whether it is useful depends on your metabolic risk, symptoms, other treatment options and goals.

What about weight-loss medicines?

For people with PMOS who also meet standard clinical criteria for treatment of overweight or obesity, anti-obesity medicines may sometimes be considered in addition to lifestyle treatment.

These decisions should follow the same principles used for obesity treatment generally.

Pregnancy planning matters because some weight-management medicines should not be used during pregnancy, and contraception may be required while taking them.

They are an option for selected people, not a treatment every person with PMOS requires.

What about mental health?

This deserves more attention than it has historically received.

People with PMOS have higher rates of:

• depression
• anxiety
• body-image distress
• disordered eating and eating disorders.

The condition can also affect confidence, relationships and sexual wellbeing.

Current guidelines specifically recommend recognising and assessing psychological health as part of PMOS care rather than treating it as unrelated to the condition.

If you are struggling emotionally, mention it.

It is part of the health picture, not an optional extra.

Does PMOS increase the risk of sleep apnoea?

Yes, obstructive sleep apnoea occurs more commonly in people with PMOS, independently of some other risk factors.

Consider discussing it with your GP if you have:

• loud snoring
• waking unrefreshed
• excessive daytime sleepiness
• witnessed pauses in breathing during sleep.

Not all fatigue in PMOS is hormonal.

What if I’m trying to become pregnant?

Tell your GP early.

Pre-pregnancy care can include reviewing:

• ovulation and cycle pattern
• medicines
• folic acid
• smoking and alcohol
• vaccinations
• blood pressure
• glucose
• metabolic health
• other fertility factors.

PMOS pregnancies have higher rates of some complications, including gestational diabetes and hypertensive disorders, so recognising the diagnosis before or early in pregnancy is useful.

But again, higher risk does not mean complications are inevitable.

Questions people commonly ask

My ultrasound says “polycystic ovaries”. Do I have PMOS?

Not necessarily.

Ovarian appearance is only one part of the diagnostic criteria.

Some people have polycystic ovarian morphology without having the syndrome.

My ultrasound is normal. Does that rule it out?

No.

If you have irregular cycles and androgen excess, an ultrasound may not even be necessary to establish the diagnosis.

Do the follicles need to be removed?

No.

The follicles seen in PMOS are not ordinary ovarian cysts that need to be drained or surgically removed.

Can I have PMOS if I’m thin?

Yes.

PMOS occurs across the weight spectrum.

Metabolic risk still deserves appropriate assessment regardless of body size.

Can PMOS be cured?

There is currently no single treatment that permanently removes the underlying tendency.

But its individual effects can often be managed very effectively.

The treatment you need at 22 may be completely different from what matters at 32 or 45.

Will I have to take the pill forever?

No.

The pill is one treatment option.

Treatment should change as your priorities change — contraception, acne, bleeding, fertility and metabolic health may matter at different stages of life.

Before your GP appointment

It helps to know:

• how often your periods occur
• how long you sometimes go without one
• whether acne or excess hair growth has changed
• whether you are trying to become pregnant
• your current contraception
• family history of diabetes
• previous blood-test results
• medicines and supplements you take
• which symptom is bothering you most.

If you can, look back over the last 6–12 months of periods rather than trying to remember everything during the consultation.

A phone calendar or period-tracking app can be useful.

When should I seek medical review sooner?

Arrange medical review if:

• periods repeatedly disappear for months
• bleeding becomes very heavy or prolonged
• you are trying to conceive and periods are very irregular
• facial or body hair increases rapidly
• your voice deepens or you develop other rapidly progressing androgen-related changes
• you develop significant depression, anxiety or disordered eating
• you have symptoms suggesting diabetes, such as marked thirst and frequent urination.

Rapidly developing androgen symptoms are not typical PMOS and deserve assessment for other causes.

Seek urgent medical care for severe pelvic pain, heavy bleeding with fainting, or if you are acutely unwell.

Sudden severe pelvic pain should not simply be attributed to PMOS.

Start with one action

If you think you may have PMOS, start by looking at your menstrual pattern.

Ask yourself:

“How many periods have I actually had over the last year?”

Then bring that information to your GP along with the symptom that matters most to you.

You do not need to arrive asking for a particular hormone panel or ultrasound.

Start with the pattern.

The bottom line

What was traditionally called polycystic ovary syndrome, or PCOS, is now called polyendocrine metabolic ovarian syndrome, or PMOS.

The new name reflects what we have understood for some time:

this is much more than a problem with ovaries or cysts.

PMOS can affect periods, hormones, skin, fertility, metabolism and emotional wellbeing.

You do not need ovarian “cysts” to have it, and an ultrasound alone cannot diagnose it.

Treatment should focus on your priorities — whether that means controlling irregular bleeding, improving acne or unwanted hair, protecting metabolic health, supporting emotional wellbeing or helping you become pregnant.

And PMOS care should evolve as your life changes.

The aim is not simply to give the condition a label.

It is to understand which parts of it matter to you now, reduce future health risks, and treat the problems that are getting in your way.