Are Thyroid problems related to Endometriosis ? – Top 5 scientific evidences

Thyroid problems both hyperthyroidism and hypothyroidism have a strong bond with endometriosis. New researches found that endometriosis can affect thyroid hormone synthesis, activation of thyroid hormones. And thyroid hormone levels are directly associated with the size of endometriotic implants. Also, studies show that patients with both thyroid diseases and endometriosis have severe long term pain.

What is endometriosis? 

The endometrium is a set of cell layers that lining the inner wall of the uterus. Endometriosis means situating these endometrium tissues outside their normal location. They can be in fallopian tubes, the ligaments which stabilize the uterus, bladder, rectum, breast, umbilicus, and basically everywhere in the body.

So why this is a problem? As we know the female body is going through cyclical menstrual changes which can be regular or irregular. In these periods endometrial cell layers are dislodged from the uterus and removed as blood and blood clots. These cyclical changes are regulated by hormones.

Because these hormones affect every endometrial tissue equally, the other places where endometrial implants are present going through this process. Therefore these people experience bleeding from any organ that these implants are located.

If they are in the lungs, blood with cough, if they are in bladder blood in the urine, if they are in the rectum blood in the stool, likewise.

And the other issue is pain. This is a severely painful situation along with that time period which most of the time women tend to resting and loading with painkillers.

In the long run, endometriosis is one of the leading causes of female infertility as implantation won’t be successful most of the time.

American society of reproductive health reported that 1 out of 10 USA women experiences this problem. And the sad story is even though it’s common, most of the women are diagnosed with endometriosis after decades of a troublesome period of life.

The connection with thyroid diseases 

Even though scientists are sure enough to say endometriosis and thyroid problems have a relationship, exact mechanisms are not fully understood. There are several studies performed on this matter and results help to identify the connection.

Autoimmune thyroid disease like Hashimoto’s thyroiditis gives first evidence on this issue. Autoimmunity means our body’s immune system attacks our own cells. In normal circumstances, our immune system can identify our own cells by their specific proteins called antigens. But in autoimmune diseases, this capability fails.

Autoimmune thyroid disease shows that immune cells attack thyroid hormones, thyroid gland, and thyroid hormone receptors in the body. These receptors are included in almost all body cells because receptors help to receive the signal from thyroid hormones.

Research performed at Université Paris Descartes shows that RNA molecules and proteins related to thyroid hormone have different characteristics in the endometrium cells of patients with endometriosis. RNA is the molecule that carries the genetic script from DNA to ribosomes to produce proteins. Even though there are no DNA alterations, RNA molecules tend to show different patterns from normal people.

The second proof is thyroxine ( T4 ) and triiodothyronine ( T3 ) levels in endometrial cells. T3 is the most active form in both of these hormones which are the key thyroid hormones. Body cells convert their T4 to T3 for effective metabolism. But in the endometrial cells, this conversation doesn’t work effectively. These cells show less T3 levels than normal body cells.

Thirdly a lab study found that thyroid hormones can increase the production of harmful reactive oxygen species ( ROS ) in ectopic endometrial cells which are located outside of the endometrium. ROS are produced even in normal cell metabolism. Effects of ROS are responsible for cellular aging and cell death. Generally, healthy cells are able to remove ROS efficiently without giving time to damage the cellular organelles. But in this situation that won’t happen.

The fourth evidence is the size of the endometrial implants. Lab studies showed that in low thyroid hormone levels implant size reduced 1.9 times and lighter 1.8 times to normal implant. But in high thyroid hormone levels, implant size increases up to 50 times from normal. It clearly shows that thyroid hormone levels directly contribute to the endometrial implant size. More thyroid hormones help to grow the implant.

And as the final evidence, a qualitative assessment of patients with endometriosis and thyroid problems shows these patients are having severe chronic pain than patients without thyroid problems. Therefore clinicians have decided to assess thyroid functions in patients with endometriosis to improve their quality of life.

Connection between Thyroid diseases and Endometriosis
Connection between Thyroid diseases and Endometriosis

Overactive thyroid and endometriosis or Grave’s disease-associated endometriosis 

Grave’s disease is common in females with endometriosis than those who haven’t. Researchers found there are possible two ways to describe this situation.

First is the autoimmunity of Grave’s disease. In Grave’s disease immune system produce autoantibodies that bind to thyroid hormone receptors. This mimics the action of thyroid hormones. It causes hyperthyroidism, thyroid gland enlargement, and Grave’s ophthalmopathy.

Endometriosis also has shown an autoimmune involvement in the disease process. Generally, autoimmune diseases are overlapped with each other. That means if a person has one autoimmune disease there is a high chance he or she can have one or more other autoimmune diseases as well.

Secondly high estrogen levels. Oestrogen is the key hormone that controls endometriosis. And researches showed that estrogen has a direct effect on maintaining Grave’s disease as well. That’s why Grave’s disease is 5 times higher in females than males.

Symptoms of Thyroid dysfunction and endometriosis 

Because both conditions can overlap, patients will get two sets of symptoms that are related to these two diseases. Thereby,

  • Fatigue
  • Poor sleep
  • Anxiety and feeling low
  • Heavy menstrual bleeding
  • Severe menstrual pain lasting a long period of time
  • Cyclical bleeding problems
  • Loss of hair
  • Weight gain
  • Difficult to get pregnant

Proper medical investigations are needed for further management in these situations. Symptoms control and managing with subfertility need to deal with in separate ways. Therefore we highly recommend going for your primary healthcare provider in this kind of situation.

Levothyroxine and endometriosis

Levothyroxine is a famous drug used in hypothyroidism. It gives thyroid hormones externally. Levothyroxine has a similar structure and function to the T4 hormone. T4 and T3 hormones are proved to increase the size of the endometrial implants. Even though there is no clear evidence about this, researchers believe that levothyroxine also can affect endometriosis in the same manner.

Therefore for endometriosis patients who are on levothyroxine need to have proper medical attention.

The summary

Thyroid problems and endometriosis have a clear relationship in which one can exaggerate other’s health issues. This can surely reduce the quality of life of a person. Therefore if any person is diagnosed with endometriosis she should be screened for thyroid disease as well. It needs to be done under the proper guidance of both physician and obstetrics and gynecologist.

Sources :

  1. Marine Peyneau, Niloufar Kavian, Sandrine Chouzenoux, Carole Nicco, Mohamed Jeljeli, Laurie Toullec, Jeanne Reboul-Marty, Camille Chenevier-Gobeaux, Fernando M. Reis, Pietro Santulli, Ludivine Doridot, Charles Chapron, and Frédéric Batteux, 2019, Role of thyroid dysimmunity and thyroid hormones in endometriosis
  2. Jin-Sung Yuk, MD, Eun-Ju Park, MD, Yong-Soo Seo, MD, Hee Jin Kim, MD, Seon-Young Kwon, MD, and Won I. Park, MD, 2016, Graves Disease Is Associated With Endometriosis

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Sapumal Edirisinghe
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