Introduction
Polyendocrine Metabolic Ovarian Syndrome (PMOS) is the updated name for the condition previously known as Polycystic Ovary Syndrome (PCOS). The new name better reflects that PMOS is not simply an ovarian condition, but a complex hormonal and metabolic condition that can affect periods, fertility, skin, weight, insulin resistance and long-term health.
PMOS better reflects what clinicians have long known: this is a condition involving multiple hormone systems, metabolism, reproductive health and long-term wellbeing.
Understanding PMOS can help women access appropriate support earlier and appreciate that their symptoms are not “all in their head” or simply related to weight gain.
Why Has PCOS Been Renamed PMOS?
The new name was introduced following international expert consensus and reflects growing understanding of the condition.
The term Polyendocrine Metabolic Ovarian Syndrome highlights three key aspects:
Polyendocrine
PMOS affects multiple hormone systems throughout the body, including:
- Insulin
- Testosterone and other androgens
- Oestrogen
- Progesterone
- Stress hormones
- Appetite-regulating hormones
Metabolic
Many women with PMOS experience metabolic dysfunction, including:
- Insulin resistance
- Weight gain
- Difficulty losing weight
- Elevated cholesterol
- Increased risk of type 2 diabetes
Ovarian
PMOS commonly affects ovulation and reproductive health, leading to symptoms such as irregular periods and fertility difficulties.
The new terminology aims to move away from the misconception that ovarian cysts are the defining feature of the condition.
How Common Is PMOS?
PMOS is one of the most common endocrine conditions affecting women of reproductive age.
It is estimated to affect approximately 6–13% of women worldwide, although many remain undiagnosed.
Some women are diagnosed during investigations for fertility difficulties, while others seek help for acne, unwanted hair growth, weight gain or irregular periods.
What Causes PMOS?
There is no single cause.
Instead, PMOS appears to develop through a combination of:
- Genetic predisposition
- Insulin resistance
- Hormonal imbalance
- Environmental influences
- Lifestyle factors
Many women have a family history of PMOS, type 2 diabetes or metabolic disease.
The Central Role of Insulin Resistance
One of the most important drivers of PMOS is insulin resistance.
Insulin is a hormone produced by the pancreas that helps move glucose from the bloodstream into the body’s cells.
When cells become less responsive to insulin, the body compensates by producing more.
These elevated insulin levels can stimulate the ovaries to produce excess androgens, including testosterone.
This may contribute to:
- Acne
- Excess facial or body hair
- Scalp hair thinning
- Irregular periods
- Difficulty conceiving
Insulin resistance can also make weight management significantly more challenging.
If you would like to learn more about this important topic, read our article: Insulin Resistance and Hormone Health: The Hidden Connection.
Symptoms of PMOS
Symptoms vary considerably between individuals.
Common symptoms include:
Menstrual Symptoms
- Irregular periods
- Infrequent periods
- Absent periods
- Heavy periods
Fertility Difficulties
- Irregular ovulation
- Difficulty conceiving
Androgen Excess
- Acne
- Oily skin
- Increased facial or body hair growth
- Scalp hair thinning
Metabolic Symptoms
- Weight gain
- Difficulty losing weight
- Increased waist circumference
- Fatigue
- Sugar cravings
Emotional Wellbeing
Many women with PMOS report:
- Low mood
- Anxiety
- Reduced self-confidence
- Difficulties with body image
Some women also notice worsening premenstrual symptoms. If this sounds familiar, you may find our article PMDD Symptoms: Understanding Premenstrual Dysphoric Disorder helpful.
How Is PMOS Diagnosed?
Diagnosis is usually based on a combination of:
Clinical History
Your clinician may ask about:
- Menstrual patterns
- Fertility history
- Weight changes
- Acne
- Hair growth patterns
Blood Tests
Blood tests may include:
- Testosterone
- Sex hormone-binding globulin (SHBG)
- LH and FSH
- Thyroid function
- Prolactin
- HbA1c
- Lipid profile
Ultrasound Scan
Some women may have polycystic ovarian morphology on ultrasound, although this is not essential for diagnosis.
Importantly, many women with PMOS do not have visible ovarian cysts.
PMOS Beyond Fertility
Historically, PMOS was often viewed primarily as a fertility condition.
We now know it can have lifelong implications for health.
Women with PMOS have an increased risk of:
- Type 2 diabetes
- Prediabetes
- High blood pressure
- Abnormal cholesterol levels
- Fatty liver disease
- Cardiovascular disease
This is why early recognition and management are so important.
PMOS and Menopause
A common misconception is that PMOS disappears after menopause.
Whilst ovulation ceases, the metabolic features often persist.
Women may continue to experience:
- Insulin resistance
- Weight management difficulties
- Increased cardiovascular risk
- Elevated androgen levels
As women approach menopause, the interaction between PMOS, changing oestrogen levels and metabolic health can become increasingly important.
Our article The Estrobolome in Menopause: Why Gut Health Matters explores another important aspect of hormonal health during midlife.
How Is PMOS Treated?
Treatment depends on individual symptoms and goals.
Management may include:
Lifestyle Interventions
- Regular physical activity
- Resistance training
- Improved sleep
- Nutritional support
- Weight management where appropriate
Hormonal Treatments
Some women benefit from:
- Combined hormonal contraception
- Cyclical progesterone
- Menopausal hormone therapy during perimenopause
Insulin-Sensitising Treatments
In some circumstances, treatments such as metformin or GLP-1 receptor agonists may be considered.
Fertility Support
Women trying to conceive may require ovulation-induction treatments or referral to fertility specialists.
The Importance of Individualised Care
PMOS affects every woman differently.
For one woman, the primary concern may be fertility. For another, it may be acne, unwanted hair growth, weight gain or metabolic health.
There is no single treatment that suits everyone.
A personalised approach that considers hormonal, metabolic and psychological wellbeing often provides the best outcomes.
Key Takeaway
Polyendocrine Metabolic Ovarian Syndrome (PMOS) is the new name for the condition previously known as PCOS.
The new terminology better reflects the reality that this is a complex hormonal and metabolic condition affecting far more than the ovaries alone.
If you are experiencing irregular periods, fertility difficulties, weight gain, acne, excessive hair growth or symptoms suggestive of insulin resistance, it may be worth discussing PMOS with a healthcare professional.
Early diagnosis and appropriate support can help improve both short-term symptoms and long-term health outcomes.
Hormones, Metabolism and Women’s Health
- PMDD Symptoms: Understanding Premenstrual Dysphoric Disorder
- The Estrobolome in Menopause: Why Gut Health Matters
- Insulin Resistance and Hormone Health: The Hidden Connection
Trusted Resources
- World Health Organization (WHO) – Polycystic Ovary Syndrome
- International Evidence-Based Guideline for PCOS
- The Endocrine Society – Patient Resources
- Verity (UK Charity for PCOS and PMOS)
Is PMOS the same as PCOS?
Yes. PMOS is the updated name for the condition previously known as PCOS.
Do you need ovarian cysts to have PMOS?
No. Many women with PMOS do not have visible ovarian cysts, which is one reason the terminology has changed.
Can PMOS affect weight?
Yes. PMOS is closely linked with insulin resistance, which can make weight management more difficult.
Does PMOS go away after menopause?
Not necessarily. Period symptoms may change after menopause, but metabolic features such as insulin resistance and cardiovascular risk may persist.
Can PMOS be treated?
Yes. Treatment depends on symptoms and may include lifestyle support, hormonal treatment, insulin-sensitising medication and fertility treatment where needed.