Educational Content: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment.

What Happens If Hypothyroidism Is Left Untreated?

Medically reviewed by Dr. Otari Nergadze, Neurosurgeon | Updated: January 2026

If hypothyroidism is not treated, it can lead to various complications
If hypothyroidism is not treated, it can lead to various complications

If hypothyroidism is not treated, it can lead to various complications, such as :

What is hypothyroidism?

Hypothyroidism occurs when the thyroid gland is unable to produce sufficient levels of thyroid hormones. The thyroid is a small, butterfly-shaped gland located in front of the neck. Thyroid hormones regulate metabolism, body temperature, heart rate, and the digestive system. A decrease in the levels of the thyroid hormone causes several body functions to slow down. Hypothyroidism tends to affect women more than men. It can begin at any age, but commonly, it affects middle-aged women. Sometimes, hypothyroidism develops after pregnancy. A thyroid problem may be diagnosed during blood tests or after symptoms begin.

There are several treatment options for hypothyroidism that are safe and effective.

What are the signs and symptoms of hypothyroidism?

The signs and symptoms of hypothyroidism in adults may include:

The signs and symptoms in babies include:

  • Yellow skin and eyes (prolonged jaundice of birth)
  • A large, protruding tongue
  • Difficulty breathing and feeding
  • Hoarse cry
  • Poor muscle tone (a protruding tummy)
  • Excessive sleepiness
  • Physical and mental retardation in untreated infants
  • Delayed milestone development

The signs and symptoms in children and young adults are the same as adults, but in addition, they may also present with:

  • Poor physical and mental development
  • Short height
  • Delayed development of permanent teeth
  • Delayed puberty

What causes hypothyroidism?

Hypothyroidism occurs when the thyroid gland does not produce sufficient thyroid hormones. Hypothyroidism may occur due to the following:

  • Autoimmune disease: Autoimmune disease (when the body’s immune system attacks its own cells) of the thyroid is also known as Hashimoto thyroiditis.
  • Hyperthyroidism treatment: Overtreatment of hyperthyroidism (production of excessive thyroid hormone) can lower thyroid hormone levels.
  • Thyroid surgery: Removing all or a large portion of your thyroid gland.
  • Radiation therapy: Radiation therapy used to treat cancer in the head and neck region can damage the thyroid gland.
  • Medications: Certain medications used in other conditions, such as lithium for psychiatric disorders, can affect the thyroid gland.
  • Congenital disease: Being born with a defective thyroid gland or no thyroid gland.
  • Pituitary disorder: The pituitary gland produces thyroid-stimulating hormone (TSH), which stimulates the thyroid gland to produce thyroid hormone.
  • Pregnancy: Antibodies against the thyroid gland may develop during or after pregnancy (postpartum hypothyroidism).
  • Iodine deficiency: Iodine is a mineral required in the synthesis of thyroid hormones. Certain places are devoid of iodine in the soil. These regions are called goiter belts. Iodine deficiency in the foods in this region makes people prone to hypothyroidism.

How is hypothyroidism treated?

Standard treatment for hypothyroidism involves thyroid hormone tablets to achieve normal TSH levels. This is achieved by the daily administration of synthetic thyroid hormone, levothyroxine. Levothyroxine is an oral medication, and the dose is adjusted by the physician based on the hormone levels in the blood. Most cases require lifelong treatment but testing at regular intervals is advised because the hormone levels in the blood fluctuate and the dosage needs to be changed accordingly.

A balanced diet, using iodized table salt in food, and regular exercise are recommended along with the medical treatment.

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