Hypothyroidism occurs when the thyroid gland does not produce enough thyroid hormone. This causes body processes (metabolism) to slow down, resulting in symptoms such as fatigue, intolerance to cold and dry skin.

Causes of hypothyroidism include autoimmune diseases, certain medications, pregnancy, damage to the pituitary gland, radiation therapy, surgery and treatment of hyperthyroidism. Potential complications of hypothyroidism include heart disease, muscle injury, cholesterol problems, infertility, birth defects or an enlarged thyroid (goiter).

Hypothyroidism can be difficult to diagnose because its symptoms vary considerably and may be found in other diseases. This illness is most common in women over the age of 50. As a result, physicians often screen for this disease during routine physical examinations of women in this age group. In other cases, a physician may check for hypothyroidism in patients who display symptoms. Thyroid blood tests aid in diagnosis.

Thyroid hormone replacement treatment can control hypothyroidism. These medications help return the body's metabolism to a normal state.