10 Common Causes of Hypothyroidism You Need to Know

Hypothyroidism is a condition characterized by an underactive thyroid gland; a butterfly-shaped gland located toward the front of your throat.

The thyroid gland is crucial for all bodily functions as it releases the thyroid hormone responsible for many organ activities including the heart, metabolism and the body’s use of energy, and body temperature regulation.

So, when this all-encompassing thyroid gland does not produce enough of the hormone, it can send your body off-kilter.

The good news is hypothyroidism is very common and easily treatable, but it may be a lifetime disease to be managed by lifestyle and medication. If left untreated, hypothyroidism can cause many life-threatening complications, so identifying the cause and getting the requisite treatment is essential.

This article lists and explains the 10 most common causes of hypothyroidism, so you can apprise yourself of risk factors, lead a healthier lifestyle, and prevent its advent or complication.

Symptoms of Hypothyroidism

  • Muscle aches, weakness, stiffness, tenderness

  • Fatigue

  • Brain fog and memory problems

  • Weight Gain

  • Depression

  • Hoarseness of voice

  • Coarse skin

  • Thinning hair

  • Irregular or heavy menstrual cycles

  • Puffy face and droopy eyes

  • Constipation

  • Heightened sensitivity to the cold

  • Numbness or a pins-and-needles sensation in your hands/fingers

Causes of Hypothyroidism

Hashimoto’s Thyroiditis

This autoimmune disorder is also referred to as chronic lymphocytic thyroiditis. In this disorder, the body’s cells Hashimoto’s thyroiditis is the leading cause of hypothyroidism.

It is an autoimmune disorder in which your system’s antibodies attack the healthy tissues of your thyroid gland, damaging it and reducing its ability to function optimally and produce enough of the thyroid hormone. This disorder is mostly hereditary and occurs more commonly among women.


Women can develop hypothyroidism when they are pregnant or postpartum. For the most part, those with hypothyroidism at the time of pregnancy are already suffering from Hashimoto’s disease – these constitute about 3% of pregnancies.

Even if they aren’t but they have hypothyroidism, this can be treated with a higher dose of thyroid medication during this period. If it isn’t treated on time, it could cause preeclampsia, stillbirths, or premature delivery.

Iodine Deficiency

This is a rare cause of hyperthyroidism because most salts available on the market are already fortified with the mineral iodine i.e., iodized salt. Since most countries have iodized salt, this possibility is rare. But too little iodine can cause goiter i.e., an enlargement or swelling of the thyroid gland and hypothyroidism, and excess iodine can also provoke hypothyroidism.

Congenital Hypothyroidism

Hypothyroidism can be present at birth – babies can be born without a thyroid gland, a partial thyroid, or a damaged thyroid gland which causes intellectual and mental health difficulties in later life, in addition to abnormal growth or brain deformities.

This problem is not always perceptible at birth which is why newborn screening always takes place to detect the possibility of a malfunctioning thyroid at birth.

Pituitary Disorders

The pituitary gland situated at the base of the brain and linked to the hypothalamus via blood vessels and nerve fibers is responsible for communicating messages to the thyroid gland to make more of the thyroid-stimulating hormone (TSH).

If there is any disorder or dysfunction of this gland, thyroid hormone production is affected. Pituitary gland disorders can also lower testosterone levels which in turn affect thyroid gland function.

Radiation Treatment

You may be more susceptible to developing hypothyroidism if you have received radiation therapy on your neck o head for cancer like Hodgkin’s disease or lymphoma. If you have received iodine radiation for hyperthyroidism i.e., an overactive thyroid, the excess of iodine can ironically lead to hypothyroidism due to damage to the thyroid cells.


People who undergo surgical removal of the entire thyroid gland i.e., both sides of the gland are at higher risk of developing hypothyroidism as are those who have a partial thyroidectomy.

Surgeries either reduce or completely stop the production of the thyroid hormone. Surgical interventions are usually for benign nodes/lumps that grow on the thyroid gland, small cancerous tumors, or to extract an enlarged thyroid due to goiter.


Specific medicines prescribed for other health conditions can affect the functioning of the thyroid gland. These include lithium for a psychiatric disorder like bipolar disorder, oncological medicines that may directly or indirectly affect the gland, or heart medications like amiodarone used for treating ventricular arrhythmias.

So consult your physician about the effect these medicines may have whether you already have hypothyroidism and are taking medication or even if you don't because certain individuals are genetically predisposed to developing hypothyroidism.

Other Causes for Hypothyroidism

  • Rare Diseases − Certain diseases may affect various organs in the body and affect the thyroid gland either directly or indirectly.

  • For example, hemochromatosis in which the body absorbs too much iron, amyloidosis in which the protein amyloid accumulates to abnormal levels in the organs impairing their function, or sarcoidosis in which inflammatory cells grow and build up on different organs in various parts of the body.

  • Autoimmune diseases − lupus, rheumatoid arthritis, celiac disease, or Sjogren’s syndrome can cause the immune system to attack its own healthy tissue including that of the thyroid gland, and cause enough damage to make it underactive.

  • Other diseases like pernicious anemia and diabetes (either type 1 or 2) can also contribute to hypothyroidism.

Treatment of Hypothyroidism

Hypothyroidism is managed for a lifetime through regular doctor’s visits and monitoring of thyroid levels. You will be prescribed a medication called levothyroxine to manage thyroid level fluctuations and the dosage will be managed according to the results of each check-up.


Getting timely treatment for thyroid is essential as it could lead to a number of complications. These include infertility as thyroid levels can interfere withs ovulation and peripheral neuropathy in which the peripheral nerves are damaged causing tingling in the extremities amongst other symptoms.

In rare cases a complication called Myxoedema coma in which the hypothyroidism is aggravated by infections, bodily stress, or sedatives can occur, causing extreme intolerance to cold temperatures, drowsiness, lethargy, and unconsciousness which needs emergency treatment.

Updated on: 14-Apr-2023


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