PMOS - Polyendocrine Metabolic Ovarian Syndrome
PMOS: What is Polyendocrine Metabolic Ovarian Syndrome?
Polyendocrine Metabolic Ovarian Syndrome (PMOS) is the new name for what was previously known as polycystic ovary syndrome (PCOS).
The name changed in 2026 to reflect that PMOS is not simply a condition affecting the ovaries. It can affect periods, fertility, hormones, metabolism, skin, hair and psychological wellbeing.
PMOS is common, affecting around 1 in 8–10 women, although many people remain undiagnosed.
The exact cause isn't known, but genetics, hormones, metabolism and environmental factors are thought to play a role.
What happens in PMOS?
PMOS is associated with changes in reproductive hormones and metabolism.
Many people with PMOS have some degree of insulin resistance. This means the body doesn't respond as effectively to insulin, the hormone that helps glucose move from the bloodstream into our cells.
The body may compensate by producing more insulin. Higher insulin levels can contribute to increased production of androgens, including testosterone, which can affect ovulation and cause symptoms such as acne and increased facial or body hair.
Not everyone with PMOS has insulin resistance, and the condition is much more complex than simply being a problem with blood sugar.
What are the symptoms?
Symptoms can vary a lot . They can include:
irregular, infrequent or absent periods
difficulty becoming pregnant
acne or oily skin
increased facial or body hair
scalp hair thinning
weight gain or difficulty managing weight
low mood or anxiety.
darker, thicker skin around the neck or skin folds (acanthosis nigricans)
You don't need to have all of these symptoms to have PMOS.
How is PMOS diagnosed?
Investigations include blood tests for testosterone, sex hormone binding globulin and other hormones including FSH, LH and oestradiol. Other bloods may include prolactin, thyroid function, diabetes screen (HBA1C) and lipids.
In adults, diagnosis is based on the Rotterdam criteria. After excluding other possible causes, two of the following three features are needed:
Irregular or absent periods
Clinical or biochemical evidence of higher androgens, such as increased facial hair, acne or raised testosterone.
Polycystic ovaries on ultrasound.
Importantly, you don't need to have polycystic ovaries on an ultrasound scan to have PMOS.
What about teenagers?
We can suspect PMOS in teenagers, but diagnosis isn’t confirmed until later, over age 20, or 8 years after periods starting. Ultrasound is not recommended for diagnosing PMOS in teenagers because the ovaries can naturally have a multiple-follicle appearance. There needs to be irregular periods, and clinical symptoms of increased androgens, or raised androgen on blood tests to suspect the diagnosis.
We treat symptoms in the same way as for adults, and monitor regularly.
PMOS, perimenopause and menopause
PMOS doesn't simply disappear when your periods stop. The average age of menopause in the UK is 51, however in women with PMOS it typically a couple of years later.
As you approach perimenopause, your menstrual cycles can naturally become more irregular. This can make it difficult to distinguish the changes of perimenopause from the irregular periods associated with PMOS.
There can also be considerable overlap in symptoms. Weight changes, sleep problems, low mood, brain fog, changes in libido and fatigue can occur during perimenopause as well as in people with PMOS.
After menopause, the reproductive features of PMOS become less obvious because periods have stopped naturally. However, some of the metabolic and androgen-related features can persist.
A history of PMOS is associated with ongoing metabolic risks, including insulin resistance, type 2 diabetes, high blood pressure, abnormal cholesterol and fatty liver disease and it is important to continue monitoring for these.
Symptoms such as facial hair, acne or scalp hair thinning can also continue after menopause.
Can I use HRT if I have PMOS?
Lifestyle measures such as strength training, regular exercise, a balanced diet, good sleep and maintaining cardiovascular health remain important through perimenopause and beyond.
HRT doesn't treat PMOS itself, but it may be appropriate for managing menopausal symptoms and you can use HRT when you have PMOS.
If you have PMOS and are experiencing symptoms of perimenopause or menopause, it's important to consider the whole picture rather than assuming every symptom is due to PMOS.
What are the longer-term health risks?
PMOS is associated with an increased risk of:
Type 2 diabetes and prediabetes
high blood pressure and other cardiovascular risk factors
sleep apnoea
depression and anxiety
non alcoholic fatty liver disease
endometrial hyperplasia (thickening of the lining of the womb) and endometrial cancer
fertility problems due to irregular ovulation.
Having PMOS doesn't mean you will develop these conditions, but it is important to consider your longer-term health as well as your symptoms.
How is PMOS treated?
There isn't one treatment for PMOS. Management depends on your symptoms, health risks and whether you're trying to become pregnant.
Lifestyle
Lifestyle plays an important part of managing PMOS and metabolic health.
Exercise
Keeping active and having regular exercise.
Exercise can include a combination of strength training and aerobic activity. Low impact, high intensity eg cycling, rowing, swimming, incline walking are good examples.
Diet - balanced diet is important, plenty of fluids through the day. Having a 10 minute walk after meals is also helpful
Gut health - having a healthy gut can help with hormone levels, insulin resistance and also reducing inflammation.
Trying to keep weight in a healthy range
Smoking - stopping if possible
Psychological support
Hormonal treatments
If you're not trying to become pregnant, the combined oral contraceptive pill can
help regulate periods
improve symptoms such as acne and excess hair
helps to keep the lining of the uterus thin.
Other treatments include hormonal coils (IUDs) and progesterone only pills.
Metformin
Metformin is a tablet that can improve insulin sensitivity and may be recommended for some people, particularly where there are metabolic risk factors. It can also help with menstrual regularity and ovulation in some women.
Acne and excess hair
There are a range of treatments for acne and unwanted hair, including topical treatments, medication, laser hair removal and electrolysis.
Excess hair growth
There are different options including a cream (eflorinthine), oral tablets, hormonal contraception. Hair removal includes cream, laser hair removal is most effective.
Fertility
If PMOS is affecting ovulation and you're trying to conceive, there are effective treatments available.
If your periods are very irregular or absent, it's worth seeking advice earlier rather than simply waiting for a year before asking for help.
What monitoring should I have?
Because PMOS can affect your longer-term health, regular monitoring is important.
This should include:
blood pressure
blood glucose/HbA1c
cholesterol
oral glucose tolerance test (OGTT) in pregnancy
weight and waist measurement where appropriate
mental health
assessment for symptoms of sleep apnoea.
The frequency of monitoring depends on your individual risk factors.
The bottom line
PMOS is much more than a condition affecting the ovaries. It can affect your periods, fertility, hormones, metabolism, skin, hair and psychological wellbeing.
The good news is that there are many effective ways to manage it. Treatment should be individualised according to your symptoms, your health and your plans for the future.
If you've been diagnosed with PCOS in the past, or think you may have PMOS, it's worth reviewing both your symptoms and your longer-term health with your GP or a healthcare professional with expertise in women's health. Please book an appointment if you’d like to discuss your symptoms or you think you may have PMOS
References:
https://cks.nice.org.uk/topics/polycystic-ovary-syndrome/
https://www.thelancet.com/journals/lancet/article/PIIS0140-67362600717-8/fulltext
https://www.monash.edu/medicine/mchri/pcos/guideline
Resources:
https://mchri.org.au/guidelines-resources/community/pmos-resources/
