Polyendocrine Metabolic Ovarian Syndrome: an Update
PCOS (Polycystic Ovarian Syndrome) has been recently renamed PMOS (Polyendocrine Metabolic Ovarian Syndrome) to more accurately reflect the complexity of metabolic, endocrine, and ovarian interconnections within the condition.
This blog explores the conceptualisation of PMOS as an evolutionary condition driven by modern lifestyle mismatches, insulin resistance, and multisystem hormonal disruption. PMOS is now being used, however currently the research refers to PCOS and it should be considered to refer to PMOS until literature catches up. The condition has not changed, and the name now better reflects the condition.
Why has the Name Changed?
The old name “polycystic ovarian syndrome” was scientifically inaccurate as women may not have ovarian cysts.
The name caused diagnostic delays, stigma, and confusion.
A global consensus (14,360 participants) selected Polyendocrine Metabolic Ovarian Syndrome (PMOS) because it better reflects the co-existence of endocrine dysfunction, metabolic dysfunction and ovarian dysfunction.
Importantly, the new name emphasises PMOS as a whole‑body condition, not just a reproductive one.
A 3‑year global implementation plan is underway.
PMOS is now recognized as a multisystem endocrine-metabolic disorder, not a ovarian disease characterised by ovarian cysts.
PMOS as an Evolutionary Mismatch Condition
The cause of PMOS isn’t always clear and there is a cause and effect quandary often. Insulin resistance and increased adipose tissue can lead to increased androgen production which can lead to PMOS presentation. Likewise, PMOS can drive androgens and metabolic dysfunction related to insulin resistance and lipid dysfunction.
There is an underlying genetic predisposition associated with PMOS and some researchers believe that PMOS is the result of ancient survival genes being out of step with our modern lifestyle. In earlier times, the patterns associated with PMOS would have been advantageous when food was less available and the environment less hospitable:
Insulin resistance once helped humans survive famine.
Higher androgens supported strength and resilience.
Lower fertility protected women from starvation or danger and reduced risk of dying in childbirth.
Efficient fat storage was adaptive in food-scarce environments.
Today, these traits become maladaptive in a world of:
Processed food and abundance
Chronic stress
Endocrine-disrupting chemicals
Circadian disruption
Sedentary living
When viewed like this, PMOS is seen as an evolutionary response that becomes problematic in modern conditions.
The good news is that this provides lots of opportunities to adapt the diet and lifestyle to reduce the impact of negative tendencies including avoiding ultra-processed, refined foods, moving more and leveraging the positives like the ability to build more muscle which supports better glucose management.
Insulin Resistance Is the Central Driver
Insulin resistance (IR) is a persistent and driving source of metabolic dysfunction:
Present in 75–85% of women with PMOS including lean women.
IR increases ovarian androgen production associated with symptoms of acne, hair loss, hirsutism.
IR disrupts ovulation and can lead to irregular cycles, anovulation and infertility.
IR drives metabolic complications like lipid dysfunction, fatty liver (Metabolic Dysfunction-Associated Steatotic Liver Disease), high blood pressure and diabetes.
Improving insulin sensitivity may be the single most impactful intervention for PMOS.
Gut Microbiome & Dysbiosis
PMOS is connected to gut microbiome specific patterns that may trigger PMOS and /or play a role in PMOS progression. The gut microbiome refers to the community of bacteria, fungi, and viruses living in the intestines that contribute greatly to overall wellness due to beneficial microbiome metabolites, gut barrier function support and hormone and neurotransmitter signalling.
Some research suggests that PMOS is associated with lower microbiome diversity (dysbiosis), more inflammatory bacteria and fewer beneficial bacteria. The gut barrier which when working optimally, prevents toxic or inflammatory particles from moving from the gut into the blood stream. Barrier dysfunction is associated with PMOS and in-turn a potential increase in inflammatory chemicals which can exacerbate insulin resistance and sex hormones function.
Modern diets can be low in fibre, higher refined carbohydrates and fat, all of which are associated with increased dysbiosis. Supporting a healthy gut through diets and lifestyle may be helpful in supporting PMOS.
Environmental Exposure to Endocrine Disrupting Chemicals
Endocrine‑disrupting chemicals (EDCs) are substances that interfere with the body’s hormone signals, almost like “chemical imposters” and can mimic or block hormone receptors. Two of the most common EDCs are BPA and phthalates.
BPA is often found in:
Plastic food containers
Water bottles
Canned‑food linings
Till receipts
Phthalates are used to make plastics flexible and appear in:
Vinyl flooring
Plastic toys
Food packaging
Cosmetics including shampoos, lotions, and fragranced items
EDCs can increase inflammation, disrupt metabolism, worsen insulin resistance, and interfere with reproductive hormones. In women with PMOS, this disruption may be more impactful due to existing sex-hormone dysregulation. Reducing chemical exposure to EDCs is a particularly meaningful lifestyle intervention if you have PMOS.
Neuroendocrine Disruption
In PMOS, the brain sends hormone signals too quickly, causing high levels of Luteinising Hormone which overstimulates the ovaries resulting in excess androgens. At the same time, another hormone (Anti-Mullerian Hormone) disrupts follicle development, leading to irregular cycles, anovulation, and the build-up of many small, immature follicles.
Stress and PMOS?
There is a correlation between PMOS and increased perceived stress on psychological stress questionnaires or stress hormone response (increased stress hormones cortisol and DHEA) when compared to women without PMOS. The evidence suggests that stress may play an important role in PMOS, potentially worsening symptoms like irregular cycles, high androgens, and metabolic issues as chronic cortisol secretion can exacerbate insulin resistance, blood glucose imbalance and the inflammatory response. Screening for stress and supporting stress management could improve PMOS outcomes.
Long-Term Health Risks of PMOS
Emerging research shows PMOS significantly increases risk for:
Cardiovascular disease
Myocardial infarction
Stroke
Gestational diabetes (diabetes during pregnancy) and Type 2 Diabetes
Fatty liver disease
Sleep apnoea
Insulin resistance and dysfunctional lipid (fat) metabolism play a key role in metabolic dysfunction. Both predispositions can lead to weight gain, particularly visceral fat within the abdominal cavity that can further exacerbate high androgens and systemic inflammation.
Visceral fat acts like a hormone‑disrupting organ in PMOS, sending out inflammatory signals that worsening insulin resistance and pushes the ovaries to make more androgens. Even small increases in this deep belly fat can intensify symptoms like irregular cycles, anovulation and metabolic stress. Even lean women with PMOS can have increased visceral fat; PMOS is not a weight-driven condition per se, however increased weight can amplify symptoms.
Lifestyle as an Effective Approach to PMOS Management
The good news is, nutrition and lifestyle interventions can consistently support PMOS associated symptoms by:
Improving insulin sensitivity
Reducing inflammation
Supporting circadian rhythm
Improving gut health
Reducing endocrine disruptors
Increasing physical activity
Improving diet quality (like fibre and glucose balance)
The role of diet and exercise
Energy‑restricted diets including Mediterranean, low‑carbohydrate, and ketogenic diets are shown to reliably reduce fat mass and improve metabolic markers especially when combined with increased exercise. Diets high in anti-inflammatories and whole foods with high fibre can support better inflammatory response and gut health.
Metabolic flexibility is increasingly associated with improved cardiometabolic function and weight management and may be particularly helpful in PMOS. The ability to switch smoothly between burning carbohydrates and fats for energy is often impaired in PMOS, where insulin resistance, visceral fat, and chronic inflammation can effectively lock the body into a metabolically rigid pattern.
Metabolic rigidity is thought to be a early pattern in cardiometabolic disease and drive problems like poor glucose handling, excess lipid storage, mitochondrial stress, and hormonal disruption.
Improving metabolic flexibility therefore may be beneficial in PMOS through strategies like exercise and dietary flexing between very low carbohydrate with high healthy fats to moderate whole carbohydrate eating. The importance on including wholefoods and avoiding refined and ultra-processed food is imperative across this pattern.
Combining structured exercise, and dietary changes may be particularly helpful. High intensity workouts are associated with improved insulin sensitivity while increased lean muscle also supports effective glucose management and insulin response. Higher androgens associated with PMOS supports the building of lean muscle. It’s like a superpower.
Dietary and exercise interventions can reliably reduce visceral fat, body mass, waist circumference, and insulin resistance, core exacerbators of PMOS pathophysiology.
Although metabolic gains may be reliably supported by diet and exercise changes, research demonstrates that hormonal outcomes can be far more variable. PMOS hormonal dysregulation may not always shift in parallel with metabolic improvements and may be influenced by the underlying cause of PMOS, which can vary. Things like baseline adiposity (fat amount and distribution) and the degree of insulin resistance may also influence.
Other things that may help:
Supporting circadian rhythm by getting morning light and reducing night time exposure to stimulating light patterns e.g. from screens 90 minutes before bed. Eating regularly and avoiding a large meal 2-3 hours before bedtime can also help the rhythm.
Stress management can help lower cortisol secretion and the risk of chronic stress and associated inflammation. Relaxation techniques including breathwork and gentle movement, gratitude journaling, and time in nature may all support better regulation. Prioritising sleep can help manage stress and support better next day food choices.
Improving gut health through adequate plant based foods which increases antioxidant capacity and provides fibre which feeds the beneficial bacteria and supports better gut barrier function. Gradually increasing fibre alongside good hydration of approximately 2.5litres/day and introducing probiotics like kefir, yoghurt, cheese, kombucha and kimchi (if tolerated) can all help. Going slowly is important to avoid rebound gastric upset.
Exposure to endocrine disrupting chemicals (EDCs) may be disproportionately disruptive for women with existing hormonal issues like PMOS and as exposure can be cumulative, therefore assessing and where possible reducing exposure may be particularly helpful.
Limiting EDC exposure can be done by making simple changes such as:
Changing a plastic water bottle to a stainless steel or a glass bottle
Asking for an electronic receipts in shops
If having take-away food, transfer food to a glass or stainless steel container, and don’t re-heat food in plastic containers
Consider an app like Yuka which will allow you to assess what you’re buying, using or consuming and suggests healthier alternatives
Key Points:
PMOS is not a random disorder. It appears to be a biological response shaped by evolution, triggered by modern lifestyle, and influenced by genetics, gut health, and environmental chemicals. PMOS better reflects the condition as a multi-metabolic, endocrine and ovarian condition.
Metabolic symptoms can be significantly improved with targeted lifestyle changes. Reproductive improvement may be more variable. One-size however does not fit all. Functional testing and personalised assessment for PMOS support may also be helpful.
Sources for further reading and listening:
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