What is PMOS?

Polyendocrine Metabolic Ovarian Syndrome (PMOS) is a hormonal and metabolic condition that affects approximately 1 in 10 women of reproductive age worldwide, making it one of the most common endocrine disorders in women. PMOS is about far more than ovaries. The condition can affect your menstrual cycle, skin, hair, weight, energy, mood, fertility, and long-term metabolic health. It is estimated that up to 70% of women with PMOS globally remain undiagnosed, and the World Health Organization recognises it as a significant public health problem that persists well beyond the reproductive years.

What does PMOS actually mean?

PMOS stands for Polyendocrine Metabolic Ovarian Syndrome. Until 2026, the condition was known as Polycystic Ovary Syndrome (PCOS), a name widely considered misleading. The “cysts” that name referred to are not true cysts but small, immature follicles on the ovaries that have not completed the ovulation process. Many women with PMOS do not have polycystic ovaries at all, and many women without PMOS do. The old name contributed to the misconception that PMOS is primarily a gynaecological condition, when it is in fact an endocrine and metabolic disorder with wide-ranging effects across the body.

That is why an international consensus process renamed the condition to Polyendocrine Metabolic Ovarian Syndrome in May 2026. Whichever name you encounter during the transition, it is important to understand that a PMOS diagnosis describes a pattern of hormonal and metabolic features, not simply an ovarian problem.

What are the symptoms of PMOS?

PMOS symptoms vary significantly from person to person. Two women with the same diagnosis can have very different experiences. Symptoms can also change over time, with new ones appearing and others improving depending on life stage, treatment, and lifestyle.

The most commonly recognised symptoms fall across several categories:

Cycle and period changes. Irregular periods, infrequent periods (fewer than 9 per year), absent periods for 3 or more months, heavy or prolonged bleeding, or unpredictable cycle lengths ranging from 28 days to several months. For some women with PMOS, particularly those with phenotype C (ovulatory PMOS), cycles may be relatively regular.

Skin and hair. Acne (often along the jawline, chin, and back), excess facial or body hair growth (hirsutism), hair thinning or hair loss on the scalp (androgenic alopecia), oily skin, and dark patches of skin (acanthosis nigricans, often on the neck or in skin folds).

Weight and metabolism. Weight gain, particularly around the abdomen, difficulty losing weight, and insulin resistance. Not all women with PMOS are overweight; PMOS affects women across all body types.

Mood and mental health. Anxiety, depression, mood swings, irritability, and reduced quality of life are well documented in PMOS research. The 2018 ESHRE/ASRM International PMOS Guideline recommends routine psychological screening for all women with PMOS.

Energy and sleep. Fatigue, low energy, sleep disturbances, and unrefreshing sleep. Women with PMOS also have a higher prevalence of sleep apnoea, particularly those with metabolic features.

Cognition. Brain fog, difficulty concentrating, and memory issues are commonly reported, though less studied than other symptoms.

Digestion. Bloating, food sensitivities, and digestive discomfort are frequently reported by women with PMOS.

Appetite and cravings. Increased hunger, strong sugar or carbohydrate cravings, and binge urges can be connected to insulin resistance and hormonal fluctuations.

For a detailed breakdown, see our complete guide to PMOS symptoms.

How is PMOS diagnosed?

PMOS is diagnosed using the Rotterdam criteria, the current international standard established in 2003 and reaffirmed in the 2018 ESHRE/ASRM guideline. A diagnosis requires the presence of at least 2 of the following 3 features, after other conditions with similar presentations have been ruled out:

1. Irregular or absent ovulation. This typically shows up as irregular periods (cycles shorter than 21 days or longer than 35 days), very infrequent periods (fewer than 9 per year), or absent periods for 3 or more months.

2. Hyperandrogenism. This can be clinical (visible symptoms like acne, hirsutism, or hair loss) or biochemical (elevated testosterone, free testosterone, DHEAS, or Free Androgen Index on blood tests). Clinical symptoms alone can suggest hyperandrogenism, but blood tests are needed for confirmation.

3. Polycystic ovarian morphology (PCOM). This is identified on ultrasound as 12 or more follicles in at least one ovary, or increased ovarian volume. Not all women with PMOS have this feature, and not all women with polycystic-appearing ovaries have PMOS.

Importantly, diagnosis also requires ruling out other conditions that can cause similar symptoms. Your doctor should test for thyroid disorders (TSH), hyperprolactinaemia (prolactin), and congenital adrenal hyperplasia (17-hydroxyprogesterone) at a minimum.

The average woman waits more than 2 years and sees 3 or more doctors before receiving a PMOS diagnosis, and 85% are dissatisfied with the information they receive along the way. For guidance on preparing for the diagnostic process, see our guide to PMOS diagnosis.

The four PMOS phenotypes

Not all PMOS is the same. The Rotterdam criteria create four distinct phenotypes based on which combination of features are present. Your phenotype affects your metabolic risk profile, which symptoms are most prominent, and which management approaches are most relevant.

Phenotype A (Classic PMOS). Irregular cycles, hyperandrogenism, and polycystic ovaries on ultrasound. All three Rotterdam criteria are present. This phenotype carries the highest metabolic and cardiovascular risk and is the most commonly studied in research.

Phenotype B (Classic without PCOM). Irregular cycles and hyperandrogenism, but no polycystic ovaries on ultrasound. Metabolic risk is similar to phenotype A.

Phenotype C (Ovulatory PMOS). Hyperandrogenism and polycystic ovaries, but with relatively regular ovulatory cycles. Androgen-related symptoms like acne, hirsutism, and hair loss are prominent, but cycle tracking may show more regular patterns. This phenotype is sometimes overlooked because the cycles appear “normal.”

Phenotype D (Normoandrogenic PMOS). Irregular cycles and polycystic ovaries, but no clinical or biochemical hyperandrogenism. This phenotype generally has lower metabolic risk than A and B.

Many women do not know their phenotype, and that is completely fine. It does not change the fact that their symptoms are real and worth tracking. Phenotype can also shift over time with treatment, lifestyle changes, or life stage transitions.

For a deeper exploration of PMOS types including the root cause framework (insulin resistant, inflammatory, adrenal, and post-pill), read our article on the types of PMOS no one tells you about.

What causes PMOS?

The exact cause of PMOS is not fully understood, but research points to a combination of genetic, hormonal, and environmental factors.

Genetics. PMOS runs in families. If your mother or sister has PMOS, your risk is higher. Research has identified multiple gene variants associated with the condition, though no single gene is responsible.

Insulin resistance. Approximately 50 to 70% of women with PMOS have some degree of insulin resistance, regardless of body weight. When cells do not respond effectively to insulin, the body produces more of it to compensate. Elevated insulin stimulates the ovaries to produce excess androgens, which disrupts ovulation and causes many of the visible symptoms.

Hormonal imbalance. Elevated levels of androgens (testosterone, DHEAS) and luteinizing hormone (LH), combined with relatively low follicle-stimulating hormone (FSH), disrupt the normal ovulatory cycle and contribute to the characteristic features of PMOS.

Chronic low-grade inflammation. Many women with PMOS show markers of chronic inflammation (elevated hsCRP, for example), which may contribute to insulin resistance and elevated androgen production.

Environmental factors. Exposure to endocrine-disrupting chemicals, chronic stress, and lifestyle factors may also play a role, though research in this area is still developing.

How is PMOS managed?

There is currently no cure for PMOS, but the symptoms can be effectively managed. Management approaches vary depending on which symptoms are most prominent, whether fertility is a goal, and what the individual's metabolic profile looks like.

Lifestyle. For women with PMOS who are overweight, the 2018 ESHRE/ASRM guideline recommends that a weight loss of 5 to 10% can significantly improve ovulation, androgen levels, and metabolic markers. Combined aerobic and resistance exercise is recommended. Importantly, no single “PMOS diet” is endorsed over others in current guidelines. Low glycaemic index diets and Mediterranean-style eating patterns have the most supporting evidence for improving insulin sensitivity, but the most effective approach is one that can be maintained long term.

Medications. Combined oral contraceptives are first-line for menstrual regulation and managing hyperandrogenism (acne, hirsutism). Metformin is guideline-endorsed for improving insulin sensitivity and may help restore ovulation. Spironolactone is used as a second-line anti-androgen for skin and hair symptoms. For fertility, letrozole is now first-line for ovulation induction per the 2018 guideline, having shown superior live birth rates compared to clomiphene citrate.

Supplements. Inositol (myo-inositol and D-chiro-inositol in a 40:1 ratio) has strong research support for improving insulin sensitivity and ovulation, though it is not yet included in all major international guidelines. Vitamin D supplementation is recommended when deficiency is confirmed, which is common in PMOS. Other supplements (omega-3, NAC, magnesium) have emerging but not yet consensus-level evidence. Always discuss supplements with your healthcare provider.

Mental health support. Given the elevated rates of anxiety and depression in PMOS, psychological support is an important part of management. Cognitive behavioural therapy (CBT) has the strongest evidence base for psychological intervention in PMOS.

For practical guidance on day-to-day management, see our guide to living with PMOS.

The PMOS diagnosis gap

Despite affecting 1 in 10 women, PMOS remains one of the most underdiagnosed conditions in women's health. Up to 70% of affected women globally do not know they have the condition. Among those who do receive a diagnosis, the average woman waits more than 2 years, sees 3 or more healthcare professionals, and 85% are dissatisfied with the information they receive.

This gap has real consequences. Delayed diagnosis means delayed access to treatment, which means more time spent dealing with symptoms that could be managed, more unnecessary distress, and a higher risk of long-term complications like type 2 diabetes, cardiovascular disease, and endometrial hyperplasia going unmonitored.

The causes of this gap are systemic: PMOS symptoms overlap with many other conditions, the old name still creates confusion, there is no single definitive test, and the care needed often spans multiple specialties (gynaecology, endocrinology, dermatology, nutrition, mental health) with no one coordinating the picture.

PMOS and long-term health

PMOS is not just a reproductive condition. It has implications for long-term metabolic and cardiovascular health that require ongoing monitoring.

Type 2 diabetes. Women with PMOS have a significantly elevated risk of developing type 2 diabetes, particularly those with insulin resistance. The Endocrine Society recommends screening with an oral glucose tolerance test for women with PMOS who have risk factors including obesity, family history of diabetes, or a history of gestational diabetes.

Cardiovascular health. ESHRE and Endocrine Society guidelines recommend cardiovascular risk assessment for all women with PMOS, not just those with visible metabolic features. Lipid panels, blood pressure monitoring, and glucose screening are part of routine PMOS care.

Endometrial health. Chronic anovulation (not ovulating regularly) results in prolonged unopposed oestrogen exposure, which can lead to endometrial hyperplasia and, over time, an increased risk of endometrial cancer. This is one of the most important reasons why cycle regulation matters medically, not just for fertility or convenience.

Mental health. Depression and anxiety are more common in women with PMOS even after adjusting for BMI and fertility concerns, suggesting they are features of the condition itself rather than simply a reaction to symptoms.

Tracking and managing PMOS with Josie

Understanding PMOS starts with understanding your own patterns. Which symptoms show up most? How do they relate to your cycle, your medications, your stress levels? Are things getting better or worse over time?

Josie is a digital health platform built specifically for the complexity of PMOS. It tracks over 50 symptoms across 8 categories, supports four distinct cycle states (including irregular and absent periods), and turns your daily data into structured appointment prep reports tailored to each specialist you see.

For women still seeking a diagnosis, Josie's Building My Case mode maps your logged symptoms to the Rotterdam criteria, giving you structured evidence to bring to appointments. For women who have been dismissed, Second Opinion Preparation provides the tools to try again with confidence.

Frequently asked questions about PMOS

Is PMOS curable?

There is currently no cure for PMOS. It is a chronic condition that can be effectively managed through a combination of lifestyle, medication, and ongoing monitoring. Many women find that their symptoms improve significantly with the right management approach, and symptoms can also shift naturally with life stage transitions.

Can you have PMOS without cysts on your ovaries?

Yes. Polycystic ovarian morphology is only one of the three Rotterdam criteria, and a diagnosis requires only two of three. Many women with PMOS (particularly phenotype B) do not have polycystic-appearing ovaries on ultrasound.

Does PMOS affect fertility?

PMOS is one of the most common causes of anovulatory infertility, meaning difficulty conceiving due to irregular or absent ovulation. However, many women with PMOS conceive naturally or with medical support. Letrozole is now first-line for ovulation induction in PMOS, with strong evidence for improving live birth rates.

What doctor should I see for PMOS?

PMOS care often involves multiple specialists. A gynaecologist or endocrinologist typically leads the diagnosis and primary management. Depending on your symptoms, you may also benefit from seeing a dermatologist (for skin and hair concerns), a nutritionist or dietitian (for dietary management), or a mental health professional. For tips on navigating this, see our appointment preparation guide.

Is PMOS genetic?

PMOS has a strong genetic component and runs in families. If your mother or sister has PMOS, your risk is higher. However, environmental factors and lifestyle also play a role, and having a genetic predisposition does not mean the condition is inevitable or unchangeable.

Does PMOS only affect overweight women?

No. PMOS affects women across all body types. While insulin resistance is more common in women who are overweight, it also occurs in women with a healthy BMI. Symptoms like acne, hirsutism, hair loss, and irregular cycles are not weight-dependent.

Can PMOS go away after menopause?

Some symptoms (particularly irregular cycles and fertility concerns) naturally resolve after menopause, but the metabolic and cardiovascular risks associated with PMOS persist. Women with PMOS should continue monitoring their metabolic health throughout their lives.

This content is for informational purposes only and is not a substitute for medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.

Sources: WHO PMOS Fact Sheet (2024); 2018 ESHRE/ASRM International Evidence-Based Guideline for the Assessment and Management of PMOS; Endocrine Society Clinical Practice Guideline; Gibson-Helm et al., Journal of Clinical Endocrinology & Metabolism, 2017.