Autoimmune Conditions and PCOS/PMOS: What We Know

Many women with PCOS or PMOS feel as though their symptoms extend far beyond periods, ovulation and fertility alone. Fatigue, digestive symptoms, brain fog, joint aches, skin changes, anxiety, hair thinning and ongoing exhaustion are all commonly reported, yet many women are told that their blood tests are “normal” or that these symptoms are simply part of having hormonal issues.

Over the last few years, researchers have become increasingly interested in the relationship between PCOS/PMOS, inflammation and immune health. In particular, studies have explored whether women with PCOS may be more likely to experience certain autoimmune conditions, especially autoimmune thyroid disease.

This does not mean PCOS/PMOS is automatically an autoimmune disease. It is currently understood as a complex endocrine, metabolic and reproductive condition. However, the research does suggest that, for some women, there may be important connections between hormones, metabolism, inflammation and the immune system.

Is PCOS/PMOS an inflammatory condition?

PCOS/PMOS is now understood to involve far more than reproductive hormones alone.

Research consistently suggests that many women with PCOS have higher levels of chronic low-grade inflammation compared with women without the condition. This does not necessarily mean there is obvious inflammation that will always be picked up on standard blood tests. Instead, it refers to subtle, ongoing activation of inflammatory pathways within the body.

Several factors may contribute to this, including insulin resistance, oxidative stress, disrupted sleep, chronic stress, altered body composition, gut health disturbances and blood sugar dysregulation. This matters because the immune system does not operate separately from the rest of the body - it is constantly responding to signals from hormones, blood sugar, the gut microbiome, stress hormones and inflammatory messengers.

Over time, a more inflammatory internal environment may affect immune tolerance. Immune tolerance is the process that helps the immune system recognise what is “self” and what is “foreign”. When this becomes dysregulated, the immune system may become more likely to react inappropriately to the body’s own tissues. That does not mean inflammation alone causes autoimmune disease. Genetics, environment, infections, stress, gut health, hormones and other triggers may all play a role.  However, this inflammatory and metabolic picture may help explain why autoimmune conditions appear more common in some women with PCOS/PMOS.

Thyroid autoimmunity and hormonal health

The strongest and most consistent autoimmune link in the research is between PCOS/PMOS and autoimmune thyroid disease, particularly Hashimoto’s thyroiditis. Hashimoto’s is an autoimmune condition where the immune system produces antibodies that target the thyroid gland. Over time, this can contribute to reduced thyroid hormone production in some people.

Several studies and reviews have found that autoimmune thyroiditis and thyroid antibodies are more common in women with PCOS compared with women without PCOS. One large 2025 study found higher anti-thyroid peroxidase antibody levels in women with PCOS, with anti-TPO antibodies positive in 12.89% of women with PCOS in that cohort. 

Subclinical hypothyroidism also appears to be more common in PCOS. A 2025 systematic review and meta-analysis of 29 studies involving 5,765 women with PCOS found that around 19.7% had subclinical hypothyroidism. It also found that women with both PCOS and subclinical hypothyroidism had higher fasting insulin and HOMA-IR, a marker of insulin resistance. 

This overlap is important because thyroid symptoms can look very similar to PCOS/PMOS symptoms. These may include fatigue, hair thinning, weight changes, low mood, brain fog, constipation, cold intolerance and irregular cycles. This is why it can be worth discussing thyroid testing with your GP if symptoms persist, especially where fatigue, hair loss, menstrual changes or unexplained changes in weight are present.

Other autoimmune conditions seen alongside PCOS/PMOS

Although thyroid autoimmunity has the strongest evidence base, newer research has started to look at other autoimmune and inflammatory conditions too.

A 2026 study looking at autoimmune diseases across different PCOS phenotypes found that organ-specific and systemic autoimmune disorders affected 22.6% of women with PCOS in their cohort. Autoimmune thyroiditis was the most common, affecting 20.3% of women. Non-thyroid autoimmune conditions were less common overall, but the most frequently reported were psoriasis, type 1 diabetes, alopecia areata and rheumatoid arthritis. 

Psoriasis

Psoriasis is an immune-mediated inflammatory skin condition. In the 2026 PCOS cohort, psoriasis was the most common non-thyroid autoimmune condition reported, although still present in a small percentage of women. 

This link is biologically plausible because both PCOS/PMOS and psoriasis are associated with inflammation, insulin resistance and metabolic risk factors. However, more research is needed before we can say whether PCOS directly increases psoriasis risk or whether shared inflammatory and metabolic pathways explain the overlap.

Type 1 diabetes

Type 1 diabetes is an autoimmune condition in which the immune system targets insulin-producing beta cells in the pancreas.

The 2026 study found type 1 diabetes among the more common non-thyroid autoimmune conditions in women with PCOS, although again at a low overall percentage. The authors suggested that autoimmune markers may be particularly relevant in women with PCOS who have dysglycaemia, because not all blood sugar problems in PCOS are necessarily driven by classic insulin resistance alone. 

This is a useful reminder that personalised assessment matters. Two women may both have PCOS/PMOS and blood sugar issues, but the underlying drivers may not be identical.

Alopecia areata

Alopecia areata is an autoimmune condition that causes patchy hair loss. This is different from androgen-related scalp hair thinning, which can occur in PCOS/PMOS.

This distinction matters because hair loss in PCOS can have several possible drivers. Higher androgen levels may contribute to female pattern hair thinning, whilst thyroid dysfunction, iron deficiency, stress, autoimmune activity and nutrient insufficiencies may also play a role.

If hair loss is sudden, patchy, rapidly worsening or associated with other symptoms, it is important to seek medical advice rather than assuming it is “just PCOS”.

Why might autoimmune conditions be more common in PCOS/PMOS?

There is unlikely to be one single explanation. Instead, the overlap probably reflects several interacting mechanisms.

Insulin resistance is one key factor. Higher insulin levels can stimulate inflammatory pathways and oxidative stress. Inflammation can then affect hormone signalling, immune regulation and metabolic health.

Hormonal patterns may also matter. PCOS/PMOS is often associated with irregular ovulation, altered progesterone exposure and higher androgen levels. Oestrogen, progesterone and androgens all interact with the immune system, which may help explain why autoimmune diseases are generally more common in women and why symptoms can fluctuate across hormonal life stages.

Adipose tissue may also contribute. Body fat is not inert tissue. It produces inflammatory signalling molecules that can influence insulin sensitivity and immune activity. This does not mean weight is the whole story, as lean women with PCOS/PMOS may also experience inflammation and autoimmune conditions. However, metabolic health is an important part of the picture.

Gut health is another area of growing interest. The gut microbiome plays a central role in immune education, inflammation and metabolic signalling. Changes in microbial diversity, gut barrier function and short-chain fatty acid production have all been explored in relation to both PCOS/PMOS and autoimmune disease.

Again, this does not mean gut support can cure autoimmune disease. However, it may form one part of a broader strategy to support immune resilience, digestion, inflammation balance and overall wellbeing.

Gut health, immune function and lifestyle factors

Because a large proportion of the immune system is associated with the gut, supporting gut health can be a useful foundation for many women with PCOS/PMOS.

This does not need to mean extreme elimination diets, expensive testing or complicated protocols. In fact, highly restrictive approaches can sometimes create more stress, reduce dietary diversity and make symptoms harder to manage long term.

A more supportive approach may include:

• Eating regular balanced meals
• Including protein at each meal
• Gradually increasing fibre from whole foods
• Eating a wide variety of colourful plant foods
• Supporting blood sugar balance
• Prioritising sleep and recovery
• Managing stress in realistic ways
• Including movement that feels appropriate for your body
• Seeking medical advice for persistent or unexplained symptoms

A Mediterranean-style dietary pattern may be particularly useful because it naturally includes fibre, polyphenols, omega-3 fats, extra virgin olive oil, legumes, vegetables, herbs, spices and oily fish. This way of eating has been widely studied in relation to metabolic and inflammatory health. For women with PCOS/PMOS, this can be a more sustainable and nourishing approach than trying to cut out more and more foods.

When to speak to your GP

It is important not to self-diagnose autoimmune conditions based on symptoms alone, as many symptoms overlap with PCOS/PMOS, thyroid dysfunction, nutrient insufficiencies, stress and other health issues.

However, it may be worth speaking to your GP if you experience:

• Persistent fatigue that does not improve with rest
• Unexplained weight changes
• Hair loss, especially if patchy or sudden
• Joint pain, swelling or morning stiffness
• Persistent digestive changes
• Recurrent rashes or skin plaques
• Cold intolerance
• Irregular, heavy or changing periods
• Brain fog or low mood
• Eye redness, pain or light sensitivity

Depending on symptoms, your GP may consider blood tests such as thyroid function, thyroid antibodies, inflammatory markers, full blood count, ferritin, B12, folate, vitamin D or referral for further assessment.

The bigger picture

The research does not suggest that every woman with PCOS/PMOS will develop an autoimmune condition. It also does not mean that PCOS/PMOS should be treated as an autoimmune disease.

However, the evidence does suggest that immune and inflammatory pathways deserve more attention.