Fast facts about hypothyroidism | NIH MedlinePlus Magazine

  • Nearly 5% of Americans over the age of 12 have hypothyroidism.

  • It is most common in women.

  • Hashimoto’s disease is a common cause of hypothyroidism. When someone has Hashimoto’s disease, their immune system attacks the thyroid, which then can’t produce enough hormones.

  • People with celiac disease, Sjögren’s syndrome, diabetes, rheumatoid arthritis, or lupus may be more likely to have an underactive thyroid.

  • If an underactive thyroid is not treated during pregnancy, women can experience high blood pressure in late pregnancy, anemia, miscarriage, low birth weight, or stillbirth.

  • Infants can also have an underactive thyroid. All newborns in the U.S. are tested for congenital hypothyroidism.