Did you know that your chances of having autoimmune thyroiditis is high if you have been diagnosed with polycystic ovary syndrome (PCOS)? It turns out there is a very strong connection between two of the most common endocrine disorders globally. Whilst the causes of these two conditions are very different, they share many common features. In fact, it is believed that these two conditions share a bidirectional relationship, which I will explain throughout this post.

What is PCOS?

Polycystic ovary syndrome, or PCOS, is an inflammatory condition that impacts hormonal balance and thus menstrual cycles. Polycystic refers to the presence of multiple fluid filled sacs (cysts) within each ovary. Common symptoms include menstrual irregularities, acne, excessive hair growth, weight gain, infertility, and mood imbalances.

The Hashimoto's & PCOS Connection

What is Hashimoto’s thyroiditis?

Hashimoto’s is an autoimmune condition where the immune system attacks the thyroid tissue located in your neck. Common symptoms include fatigue, weight gain, increased sensitivity to cold, constipation, difficulty concentrating, period irregularities, hair loss, pain and more. Hashimoto’s is three times more common in women with PCOS than women without.

What is the connection between Hashimoto’s and PCOS?

There are several bidirectional relationships between these two conditions.


The Hashimoto's & PCOS Connection

The impact of FSH/LH Ratio on prolactin and TSH

Both prolactin and TSH can contribute towards the development of cysts on the ovaries. In primary hypothyroidism, we see a rise in thyrotropin-releasing hormone (TRH). This leads to increased prolactin and the thyroid stimulating hormone (TSH).

Follicle stimulating hormone (FSH) and luteinising hormone (LH) are both released by the pituitary gland (a pea size gland located at the base of your brain). The ratio of this can impact prolactin levels, which can inhibit ovulation.

Increased TSH also contribute to PCOS due to its spill-over effects on FSH receptors.

A study with 26 women with primary hypothyroidism, identified that all 26 women had significantly higher ovarian volumes than the control group (women with no thyroid or PCOS). Ten of the 26 hypothyroid females had PCOS.


The Hashimoto's & PCOS Connection

The weight-gain connection

A further connection between both is the increase in BMI and insulin resistance. A very common symptom for both Hypothyroidism/Hashimoto’s and PCOS.

This connection is predominantly based on two pathways. The first is where a higher BMI reduces the amount of T4 (inactive thyroid hormone) being converted to T3 (active thyroid hormone). The second pathway is where higher leptin in people who are overweight can lead to increased secretion of Thyrotropin releasing hormone (TRH).

Both these pathways lead to an increase in fat cells (adipose cells), thus leading to weight gain.

Studies have shown that visceral adipose tissue volume is a good predictor for TSH levels. The greater the weight, the higher the TSH.

Interestingly, some studies have also highlighted that metformin can be successful in reducing TSH levels in clinical and subclinical hypothyroid individuals who were either taking T4 replacement therapy or not. Metformin did not have the same effect on TSH in individuals with normal thyroid function.

The inflammation connection

Studies have shown that increases in TSH result in the increase in production of pro-inflammatory markers from adipocytes (fat cells). This can further exacerbate the weight-gain connection, but also spill into the autoimmune connection.

The Hashimoto's & PCOS Connection

Autoimmune connection

Thyroid autoimmunity seems to be higher in women with PCOS.  Women with PCOS tend to have higher antibody levels and greater levels of inflammation in the thyroid. Whilst the pathophysiology of this remains unclear, one explanation for this is excess oestrogen.

Oestrogen influences the development and functions of T cells as well as cytokine production (both important aspect of immune function), which can impact the development of autoimmune diseases. It is important to note that other autoimmune conditions have also been associated PCOS.

The connection with weight and autoimmunity is further strengthened by the fact that increased leptin downregulates regulatory T-cells, thereby reducing the immune system’s ability to function optimally.

The UK Medical Research Council conducted a study with 1277 women and 1185 men aged 60-64 to look at the impact of weight on Thyroid antibodies. Weight was recorded at birth, age 2, 4, 6, 7, 11, 15 and then repeatedly into adulthood. They found that childhood weight gain and being overweight in adulthood increased susceptibility for autoimmunity, especially in women.

Another study comprising of 827 women with PCOS with reproductive and metabolic complaints, found that autoimmune thyroiditis is more common in women with PCOS than in controls. This particular study did find that these women were less likely to suffer from higher levels of androgen hormones and more from an elevated metabolic risk.

Where does this connection leave you?

If you have been diagnosed with PCOS, then there is a very good chance that you may have Hashimoto’s. It is therefore important that you get the right blood tests done to ensure that you are not missing a key part of the jigsaw. Looking at the conventional markers of T4 and TSH is not going to provide you with the full picture. To understand more, you can read ‘The best blood makers to test for optimising your thyroid health’.

There is so much you can do to support yourself if you are dealing with both Hashimoto’s and PCOS. In my group programme we go through all the key areas that you need to focus on and steps that you can take to improve your health.

Some of these include:

  • Getting the right testing done
  • Making sense of your hormones
  • Working on digestion and gut health
  • Understanding how to support your liver
  • Reducing inflammation through diet and lifestyle
  • Understanding your personal insulin response and how best to support this
  • What food is going to offer the best support
  • Which supplements to take at which points on your journey to wellness
  • How your thoughts can positively influence your health
  • And so much more.

If you are interested in joining my 3-month group programme, then make sure to book in for a free breakthrough call with me to see whether this programme is right for you. I am offering £500 off for everyone registering in February, so make sure to make the most of this amazing discount.

I also offer a 1:1 programme for those individuals with very complex health profiles.

Nutritional Therapist Cheshire, Health, Nutritionist Cheshire, Functional Medicine Cheshire, Rootcause Solution


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