PMOS: Symptoms, Diagnosis, Treatment and Causes

Irregular periods, persistent acne, unwanted facial hair or changes to your weight can feel unrelated. But when several of these changes happen together, PMOS may be one possible explanation.

PMOS stands for polyendocrine metabolic ovarian syndrome. Until May 2026, it was called polycystic ovary syndrome, or PCOS. The new name reflects that the condition can affect hormones, metabolism and reproductive health, not only the ovaries.*

Having one symptom does not mean you have PMOS. Other conditions can cause similar changes, so a proper assessment matters. Here is what to look for, how PMOS is diagnosed and the treatments that may help.

*Teede HJ, et al. (2026). Polyendocrine metabolic ovarian syndrome, the new name for PCOS.

What Is PMOS, Formerly PCOS?

PMOS is a common hormonal and metabolic condition. It affects around 10 to 13% of reproductive age women worldwide, although many remain undiagnosed.*

PMOS can affect how often your ovaries release an egg, which is called ovulation. It can also increase the levels or effects of androgens, which are hormones everyone produces, and include testosterone. 

Many women with PMOS also have insulin resistance. This means the body does not respond to insulin as well as it should, which can make it harder to manage blood sugar levels.

You can have PMOS at any weight, and symptoms vary widely. You do not need to have every symptom or have ovarian cysts to be diagnosed.

*World Health Organization. (2026). Polycystic ovary syndrome.

What Are the Symptoms of PMOS?

PMOS can affect periods, hair, skin, fertility, metabolic health and emotional wellbeing. Symptoms often begin around puberty, but some women do not notice them until later, such as when they stop hormonal contraception or try to become pregnant.*

*NHS (2026). Polyendocrine metabolic ovarian syndrome (PMOS). 

Periods and ovulation

PMOS can disrupt ovulation, making periods less predictable. You may have:

• Periods that are less than 21 days apart or more than 35 days apart

• Fewer than 8 periods a year

• Gaps of more than 90 days between periods

• No periods at all, known medically as amenorrhoea

• Difficulty becoming pregnant because you aren’t regularly ovulating

Some women with PMOS have regular bleeding but do not ovulate every month. A blood test for progesterone may sometimes be used to check whether ovulation is happening.

Painful periods are not a defining sign of PMOS. If period pain is severe or getting worse, speak to a GP because conditions such as endometriosis can cause similar symptoms.

Hair and skin changes

Higher levels or stronger effects of androgens can affect your hair and skin. Androgens are hormones such as testosterone. Possible changes include:

• Thicker or darker hair on the face, chest, stomach, or back, also known as hirsutism

• Gradual thinning around the parting or crown, known as female pattern hair loss

• Oily skin or persistent acne

• Darker, thicker patches of skin, often around the neck, armpits or groin. This is called acanthosis nigricans and can be a sign that your body is not responding to insulin as well as it should.

• Hair loss or acne on its own is not a strong sign of PMOS. A clinician may also look for other causes, including thyroid problems, iron deficiency, medicines and other hormonal conditions.

Weight and metabolic health

Some women with PMOS gain weight more easily or find weight loss more difficult. But you can still have PMOS if you are slim. Excess weight does not cause PMOS, but a higher weight and insulin resistance can make some symptoms and metabolic risks more noticeable.

Fatigue is also commonly reported, although it has many possible causes. Tell your GP if tiredness is persistent, particularly if you also snore, wake feeling unrefreshed or feel very sleepy during the day, as PMOS is associated with a higher likelihood of obstructive sleep apnoea. This is a condition in which breathing repeatedly stops and starts during sleep.*

*NHS. (2026). Sleep apnoea.

Mood and wellbeing

PMOS can affect more than physical health. Anxiety, depression, concerns about fertility, changes to appearance and difficult experiences with weight stigma can all affect quality of life. Current guidance recommends that women with PMOS are asked about anxiety, depression, body image and disordered eating so that support can be offered when needed.*

*Teede HJ, et al. (2023). Recommendations from the 2023 international evidence based guideline for the assessment and management of polyendocrine metabolic ovarian syndrome.

When should you see a GP?

Speak to a GP if you think you may have PMOS or your symptoms are affecting everyday life, work, relationships or how you feel about yourself.*

It is particularly important to get advice if:

• Your periods are consistently irregular, more than 90 days apart or have stopped

• You are finding it difficult to become pregnant

• You have new unwanted facial or body hair, persistent acne or scalp hair loss

• You have very heavy bleeding, bleeding between periods or severe pelvic pain

Rapid changes, such as a suddenly deeper voice or quickly increasing facial hair, need prompt assessment because they can have causes other than PMOS.**

*NHS. (2026). Polyendocrine metabolic ovarian syndrome (PMOS).

**Teede HJ, et al. (2023). Recommendations from the 2023 international evidence based guideline for the assessment and management of polyendocrine metabolic ovarian syndrome.

How Is PMOS Diagnosed

There is no single PMOS test. A clinician will ask about your periods, symptoms, medicines, family history and whether you are trying to become pregnant. They may also check your blood pressure, weight and signs such as unwanted hair growth, acne or skin changes.

Before confirming PMOS, they will consider other conditions that can cause similar symptoms, including thyroid problems, high prolactin levels and some adrenal conditions.

What criteria are used to diagnose PMOS?

In adults, PMOS is usually diagnosed when at least 2 of the following 3 apply. A clinician will also check that another condition is not causing your symptoms:

1. Irregular or absent periods. This can mean your ovaries are not regularly releasing an egg, which is known as ovulation.

2. Signs of higher androgen levels or activity. Androgens are hormones such as testosterone. Signs can include excess facial or body hair, known as hirsutism, acne or thinning hair. A blood test may also show raised androgen levels.

3. A higher number of small follicles in the ovaries. Follicles are small sacs where eggs develop. They can be seen on an ultrasound. In some adults, an anti Müllerian hormone, or AMH, blood test may be used instead to assess this.

Despite the name PMOS, these follicles are not ovarian cysts. You may not need an ultrasound or AMH test if you already have irregular periods and clear signs of higher androgen levels or activity.

What blood tests might you have

Blood tests may check testosterone and other hormones. They can also help rule out other conditions that could be causing your symptoms.

After diagnosis, your clinician may check your blood sugar and cholesterol. This is because PMOS can increase the likelihood of developing type 2 diabetes and other health problems.

A fasting insulin test is not usually recommended. Current tests cannot measure insulin resistance accurately enough for routine PMOS care.

Do you need an ultrasound?

You do not always need an ultrasound. It may be helpful when the diagnosis is unclear, but it is usually unnecessary if you already have irregular periods and clear signs of higher androgen levels or activity.

In some adults, an AMH blood test may be used instead of an ultrasound. AMH stands for anti Müllerian hormone. It should not be used on its own, and having both tests could make PMOS appear more likely when another explanation may be responsible.

How is PMOS diagnosed in teenagers?

Irregular periods and acne can be common for several years after puberty, which makes PMOS harder to diagnose in teenagers. Current international guidance requires both ongoing problems with ovulation and signs of higher androgen activity. Ultrasound and AMH are not recommended for diagnosis during adolescence because normal puberty can produce similar results.*

*Teede HJ, et al. (2023). Recommendations from the 2023 international evidence based guideline for the assessment and management of polyendocrine metabolic ovarian syndrome.

How Is PMOS Treated

There is no single treatment for PMOS. Your options depend on which symptoms matter most to you, your wider health and whether pregnancy is a current goal. You may need a combination of treatments, and these can change over time.

Treatment for irregular or absent periods

Hormonal contraception can make bleeding more regular and help prevent the lining of the womb from becoming too thick. The combined pill and certain progesterone only pills may also help with acne and unwanted facial or body hair.

Other options include a hormonal coil or implant. If you are not using hormonal contraception and have very infrequent periods, a clinician may prescribe a short course of a hormone called progestogen to protect the womb lining.

Treatment for unwanted hair and acne

The combined pill can help with unwanted hair growth and acne for some women. Hair removal options include shaving, waxing, hair removal creams, laser treatment and electrolysis. Laser treatment can reduce facial hair, although several sessions may be needed.

If these options have not helped enough, an antiandrogen medicine such as spironolactone may sometimes be considered. Spironolactone reduces the effect of androgens on the skin and hair follicles. It must be used with effective contraception when pregnancy is possible because it could affect the development of a baby.*

*Teede HJ, et al. (2023). Recommendations from the 2023 international evidence based guideline for the assessment and management of polyendocrine metabolic ovarian syndrome.

Treatment for scalp hair loss

PMOS can contribute to female pattern hair loss, but it is not the only possible cause. A clinician may check for other factors and recommend a treatment such as minoxidil if suitable. An antiandrogen such as spironolactone may sometimes be considered, although evidence specifically in women with PMOS remains limited.*

*British Association of Dermatologists. (2024). Hair loss female pattern androgenetic alopecia.

Support with weight and metabolic health

Some women with PMOS have insulin resistance, which means the body does not respond to insulin as well as it should. This can make blood sugar and weight harder to manage. However, you can have PMOS at any weight.

Healthy eating, regular movement, sleep and emotional wellbeing are important parts of PMOS care. There is no specific PMOS diet or type of exercise that works best for everyone. If you are living with overweight or obesity, losing even a modest amount of weight may improve insulin resistance and help periods and ovulation become more regular.

Weight loss medication

Medical weight loss treatments such as Wegovy® and Mounjaro® may be suitable for some women with PMOS who meet the usual eligibility criteria. They reduce appetite, help you feel full for longer and support the way your body manages blood sugar.

By supporting weight loss and improving insulin resistance, these medicines may also help periods and ovulation become more regular. However, they are not currently licensed specifically for PMOS and do not directly treat every symptom.

Common side effects include feeling sick, diarrhoea, constipation and vomiting. Weight loss medicines must not be used during pregnancy. Mounjaro® can also temporarily reduce the effectiveness of the contraceptive pill, because it slows how quickly the stomach empties, which can affect how well the pill is absorbed. If you take Mounjaro® alongside the pill, use an additional barrier method, such as condoms, for 4 weeks after starting treatment and for 4 weeks after every dose increase, or speak to your clinician about switching to a non-oral method of contraception.*

*Medicines and Healthcare products Regulatory Agency. (2026). GLP 1 medicines for weight loss and diabetes: what you need to know.

Metformin

Metformin helps the body respond better to insulin and manage blood sugar. It may be prescribed for PMOS, particularly when someone has insulin resistance or a higher risk of type 2 diabetes. It may also help periods become more regular, although it is not primarily a weight loss medicine.*

*Teede HJ, et al. (2023). Recommendations from the 2023 international evidence based guideline for the assessment and management of polyendocrine metabolic ovarian syndrome.

Mental health support

Talking therapy, medication or a combination may help if PMOS is affecting your mood, body image, eating or relationships. Treating physical symptoms that are causing distress can also form part of your mental health support. Speak to a GP if you are struggling, and seek urgent help by calling 111 or 999 if you feel at risk of harming yourself.

Can PMOS Affect Fertility and Pregnancy?

PMOS can make it harder to become pregnant if your ovaries do not release an egg regularly. However, it does not mean you cannot become pregnant. Many women conceive naturally, while others need treatment.*

A clinician may check whether you are ovulating and whether anything else could be affecting fertility. Letrozole is usually the first medicine considered when irregular ovulation is the main reason someone is finding it difficult to conceive. It encourages the ovary to release an egg.

Other options may include clomifene, metformin, hormone injections or in vitro fertilisation, known as IVF. The most suitable option depends on your health and whether other fertility factors are involved.

*Teede HJ, et al. (2023). Recommendations from the 2023 international evidence based guideline for the assessment and management of polyendocrine metabolic ovarian syndrome.

What Are the Long Term Health Effects of PMOS?

PMOS is associated with a higher likelihood of several health problems. Your individual risk depends on factors such as age, family history, blood pressure, weight, smoking and blood sugar levels.

Possible long term effects include:

• Prediabetes, where blood sugar is higher than normal, and type 2 diabetes

• High blood pressure or unhealthy cholesterol levels

• Obstructive sleep apnoea, which causes breathing to stop and start during sleep

• A build up of fat in the liver

• Anxiety, depression, difficulties with eating and concerns about body image

• Thickening of the womb lining, known as endometrial hyperplasia

PMOS is associated with a higher risk of cancer of the womb lining, known as endometrial cancer. However, the overall chance of developing it remains low, so routine cancer screening is not recommended solely because you have PMOS. Managing very infrequent periods with cycle regulation or progestogen can help protect the womb lining.*

After diagnosis, your clinician may check blood pressure, blood sugar and cholesterol, and new draft guidance suggests an annual check-in with your GP or clinician to review your symptoms and treatment. Blood sugar should usually be reassessed every 1 to 3 years, depending on your personal risk factors.

*Teede HJ, et al. (2023). Recommendations from the 2023 international evidence based guideline for the assessment and management of polyendocrine metabolic ovarian syndrome.

What Causes PMOS?

The exact cause of PMOS is not known. It probably develops through a combination of genetic, hormonal and metabolic factors.

PMOS can run in families. Insulin resistance may lead the body to produce more insulin, which can encourage the ovaries to make more androgens. Higher androgen activity can then interfere with ovulation and contribute to symptoms such as unwanted hair growth, acne and scalp hair loss.

Diet, activity levels or body weight do not cause PMOS. These factors can influence some symptoms and health risks, but women of any weight can have the condition.

Can PMOS Be Prevented?

There is currently no known way to prevent PMOS. Healthy eating, physical activity, enough sleep, not smoking and attending recommended health checks can support your general health and reduce some associated risks. These steps can be useful whether or not they lead to weight loss.*

*Teede HJ, et al. (2023). Recommendations from the 2023 international evidence based guideline for the assessment and management of polyendocrine metabolic ovarian syndrome.

PMOS: The Bottom Line

PMOS can affect periods, hair, skin, weight, fertility and emotional wellbeing, but it looks different for every woman. You do not need ovarian cysts or every possible symptom to have it.

If your periods are consistently irregular or you are concerned about changes to your hair, skin or fertility, speak to a GP. Understanding what is causing your symptoms is the first step towards finding treatment that matches your health and priorities.

FAQs

Is PMOS the same as PCOS?

Yes. Polyendocrine metabolic ovarian syndrome is the new name for polycystic ovary syndrome. You may continue to see PCOS used in older medical records, research and patient information.*

*Teede HJ, et al. (2026). Polyendocrine metabolic ovarian syndrome, the new name for PCOS.

Can you have PMOS with regular periods?

Yes. Some women bleed regularly but do not ovulate every month. Others meet the diagnostic criteria through signs of higher androgen activity and ovarian changes. A progesterone blood test may sometimes help confirm whether ovulation is happening.

Does PMOS go away after menopause?

PMOS is considered a lifelong condition, although periods and some symptoms change after menopause. Androgen related symptoms and metabolic risks can continue, so ongoing health checks may still be useful.*

*Teede HJ, et al. (2023). Recommendations from the 2023 international evidence based guideline for the assessment and management of polyendocrine metabolic ovarian syndrome.