Hypothyroidism is a condition where the thyroid gland does not produce enough hormones. It is oftentimes caused by an iodine deficiency, but can be caused by many other factors.

This upsets the balance of chemical reactions within the body, which over time can lead to various health problems. In infants, severe hypothyroidism can lead to cretinism, a condition where a child will be afflicted with stunted physical and mental growth.

Hypothyroidism can be treated with a synthetic thyroid hormone.