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Endometriosis, Hypothyroidism, and Hashimoto’s: What’s The Connection?

New research shows a link between endometriosis and thyroid disorders, including autoimmune Hashimoto’s thyroiditis and hypothyroidism.
Endometriosis, Hypothyroidism, and Hashimoto’s: What’s The Connection?
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When you’re doubled over in pain from endometriosis, your thyroid may be the last thing on your mind. But if you’re one of the 5 to 10% of women of reproductive age who suffer from this sometimes debilitating condition, you need to put your thyroid health on your radar. Ahead, a look at the thyroid-endometriosis connection.

What is endometriosis?

Endometriosis is an often painful condition where the tissues that line the uterus (called “the endometrium”) start growing outside the uterine walls. Endometriosis is usually found around reproductive organs and the tissues of the pelvis but can sometimes extend into other areas.

Many cases of endometriosis go undiagnosed, and on average, it can take 4 to 11 years from the onset of symptoms to get a diagnosis.

What are the symptoms of endometriosis?

One of the main signs – and complications – of endometriosis is infertility, or difficulty getting pregnant.

According to the Office on Women’s Health at the U.S. Department of Health and Human Services, the other signs and symptoms of endometriosis include:

  • Painful, heavy, or irregular menstrual periods.
  • Pain, including menstrual cramps, back and pelvic pain, pain during or after sex, intestinal pain, and pain when urinating or having a bowel movement.
  • Bleeding or spotting between menstrual periods.
  • Digestive problems, including bloating, diarrhea, constipation, and nausea. The issues are often more severe during menstrual periods.

Risk factors for endometriosis

You’re at higher risk for endometriosis if you fall into any of the following categories:

  • You have never given birth.
  • You started your period early (or had a late menopause).
  • You have short menstrual cycles (under 27 days).
  • You have high estrogen levels.
  • You have a low body mass index (BMI).
  • You have close family members – i.e., a mother, sister, or aunt – with endometriosis.
  • You have a reproductive disorder or a medical condition that prevents blood from leaving the body during menstruation.

While there’s no cure for endometriosis, treatments – including pain medications, hormone therapy, and surgery – can help relieve symptoms in some women.

What is the relationship between thyroid disease and endometriosis?

While limited, the currently available research on hypothyroidism, autoimmune disorders like Hashimoto’s thyroiditis and Graves’ disease, and endometriosis points to some interesting connections.

According to research published in 2019 in the Proceedings of the National Academy of Sciences, thyroid stimulating hormone (TSH) helps significantly increase the number of endometrial cells. Researchers concluded that because endometrial cells are susceptible to TSH variations, thyroid hormone plays a role in endometriosis. These findings are similar to those published by the Paris Descartes University, which found that cells affected by endometriosis have changes in thyroid hormone levels, specifically increased T4 and reduced T3 levels. This imbalance can lead to thyroid dysfunction.

These findings have led researchers to two important conclusions:

  1. An increased TSH level – consistent with hypothyroidism – can aggravate and worsen endometriosis.
  2. An increase in thyroxine (T4) levels – consistent with hyperthyroidism – can aggravate endometriosis.

While the good news is that there doesn't appear to be any evidence that having a thyroid condition puts you at higher risk of developing endometriosis, one study has found that women with thyroid disease who also have endometriosis tend to have a more severe form of endometriosis, with higher levels of chronic pelvic pain.

Finally, endometriosis patients are also at a higher risk of autoimmune thyroid diseases – including both Hashimoto’s thyroiditis and Graves’ disease. In one study, researchers found that, compared to women from the general U.S. population, women with endometriosis were at least six times more likely to have autoimmune hypothyroidism. Rates of Graves’ disease are also higher in women with endometriosis. Researchers have theorized that endometriosis should be characterized as an autoimmune disease, pointing to genetic markers in endometriosis that correlate to other autoimmune conditions, including autoimmune thyroid disease. 

If you have endometriosis

If you have endometriosis, you should monitor yourself for a full range of possible thyroid symptoms and undergo periodic tests and screening for thyroid dysfunction.

Some of the symptoms experienced by patients with endometriosis and thyroid disease are the same, making it confusing to identify thyroid issues in some cases. For example, crossover symptoms of thyroid problems and endometriosis include heavy or irregular periods, fatigue, pain, constipation, and infertility. 

Most importantly, as experts have recommended, if you have endometriosis, your physician should take into account your thyroid function and the possible need for thyroid hormone medication.

A note from Paloma Health

Timely diagnosis of thyroid conditions and treatment to maintain optimal thyroid function appear to be factors that may aid in the successful treatment of endometriosis. If you’re interested in regular thyroid screening, the Paloma Complete Thyroid Blood Test kit can make thyroid testing easy, convenient, and affordable, letting you test the function of your thyroid gland right from home. The Paloma home thyroid test kit includes everything you need for sample collection and testing of thyroid stimulating hormone (TSH), free T3, free T4, and Thyroid Peroxidase (TPO) antibody levels. Your thyroid test kit is sent directly to your address, and only requires an easy finger prick. You send back your sample to the lab with Paloma’s pre-paid shipping. Your thyroid lab results are then released to your secure online dashboard within days, similar to the wait time for in-person lab results—without the inconvenience.

For hypothyroidism diagnosis and treatment, we invite you to schedule a virtual visit with one of our top thyroid doctors. Paloma’s thyroid practitioners will work with you to prescribe whichever thyroid medication can safely normalize your thyroid function and help you get your hormonal systems back into balance for better health.


Sinaii N, Cleary SD, Ballweg ML, Nieman LK, Stratton P. High rates of autoimmune and endocrine disorders, fibromyalgia, chronic fatigue syndrome and atopic diseases among women with endometriosis: a survey analysis. Human Reproduction. 2002;17(10):2715-2724. doi:10.1093/humrep/17.10.2715

OASH. Endometriosis | Published January 30, 2019.

Peyneau M, Kavian N, Chouzenoux S, et al. Role of thyroid dysimmunity and thyroid hormones in endometriosis. Proceedings of the National Academy of Sciences. 2019;116(24):11894-11899. doi:10.1073/pnas.1820469116

Yuk JS, Park EJ, Seo YS, Kim HJ, Kwon SY, Park WI. Graves Disease Is Associated With Endometriosis: A 3-Year Population-Based Cross-Sectional Study. Medicine. 2016;95(10). doi:10.1097/MD.0000000000002975

What are the treatments for endometriosis? Published January 31, 2017.

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Mary Shomon

Patient Advocate

Mary Shomon is an internationally-recognized writer, award-winning patient advocate, health coach, and activist, and the New York Times bestselling author of 15 books on health and wellness, including the Thyroid Diet Revolution and Living Well With Hypothyroidism. On social media, Mary empowers and informs a community of more than a quarter million patients who have thyroid and hormonal health challenges.

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