Hypothyroidism is a common medical condition that occurs when your body does not have enough thyroid hormone.

Low thyroid hormone levels can happen if the thyroid gland does not produce enough thyroid hormones or after thyroid surgery where the thyroid is removed.

The thyroid gland is a small, butterfly-shaped gland located in the neck. The thyroid hormone regulates the body’s metabolism.

Symptoms of hypothyroidism can include fatigue, weight gain, dry skin, hair loss, and depression.

Diagnosis can be made by checking the thyroid-stimulating hormone (TSH), which is produced by the pituitary gland and regulates the level of active thyroid hormones.

There is also a wide range of normal thyroid hormone levels because everyone’s body is different, and other factors can affect the levels such as whether an individual has an acute illness, chronic medical conditions, pregnancy, and certain medications. 

Normal TSH (thyroid-stimulating hormone) level is 0.4 to 4.0 milli-international units per liter (mIU/L). There are more narrow TSH level goals during pregnancy.

Complications of hypothyroidism can include infertility, high cholesterol, and heart disease. In severe cases, a rare condition called myxedema coma can occur, which is a medical emergency.

Treatment for hypothyroidism typically involves thyroid hormone replacement therapy, which involves taking a daily medication to replace the missing hormones. Dosage may need to be adjusted over time, and regular monitoring of thyroid hormone levels is important.