Abnormally low activity of the thyroid gland which can result in retardation of growth and mental development in children and adults.

Also Known As


  • Hashimoto’s Thyroiditis (most common cause). Auto-immune disease.
  • Over-response to hyperthyroidism treatment.
  • Thyroid surgery. Removal of all or part of the thyroid gland can decrease hormone production.
  • Radiation therapy to treat cancers of the head and neck.
  • Medications (e.g. lithium)
  • Congenital disease. Some children are born with a defective gland, or no gland at all, which can lead to retardation of growth and mental development.
  • Pregnancy. Left untreated, hypothyroidism increases the risk of miscarriage, premature delivery and preeclampsia, and can seriously affect the developing fetus.
  • Pituitary disorder. Relatively rare. The pituitary gland is unable to produce enough thyroid stimulating hormone (TSH).
  • Iodine deficiency. While still common in some parts of the world without access to seafood or seaweed, the addition of iodine to table salt has virtually eliminated this form of deficiency in the United States.


  • About 4.6% of the United States population has hypothyroidism
  • More than 12% of the U.S. population will develop a thyroid condition during their lifetime.

Risk Factors

  • Age (more common in those aged 60 years and older)
  • Gender (women are more likely than men)


There is no way to prevent hypothyroidism, but people who may have a higher risk of thyroid problems, for example, women during pregnancy, should check with their doctor about the need for additional iodine.


The CDC recommends that all adults keep their vaccinations up to date. Childhood immunizations may wear off after time and need a “booster shot,” and you are at risk for other diseases as an adult.

All adults need:

  • Influenza vaccine (every year)
  • Tdap vaccine (if they did not receive it as an adolescent to protect against pertussis (whooping cough), and then a Td (tetanus, diphtheria) booster shot every 10 years.

Check with your doctor to see if there are other vaccines recommended for you.

COVID-19 and Hypothyroidism

Thus far, there is no indication that patients with autoimmune thyroid disease (i.e. Graves’ disease) are at greater risk of getting COVID-19 or of being more severely affected should they acquire the COVID-19 infection.


Support Groups