When the thyroid gland doesn't make enough thyroid hormone, it's called hypothyroidism. Congenital hypothyroidism is when the disorder is present in a baby at birth. If not treated, it can lead to serious health problems.

The thyroid is a gland. It's located in the neck just below the voice box. The thyroid gland makes thyroid hormones. These hormones help control metabolism. This is the rate at which every part of the body functions. Thyroid hormones keep the metabolism at a healthy pace. This helps the brain, heart, muscles, and other organs work well. A normal metabolism also helps make sure of a healthy temperature, heart rate, energy level, and growth rate. If a baby doesn't make enough thyroid hormones, it can cause serious problems, such as mental disability, growth delays, or loss of hearing. The condition needs to be treated as soon as possible to lower the chance of long-term problems.

The most common cause of congenital hypothyroidism is failure of the thyroid gland to grow before birth. Sometimes the gland is present but doesn't make the thyroid hormones. Other times the thyroid gland is located in an abnormal place in the neck. This makes it work less well. Or it can be caused by treatment of a thyroid problem while you are pregnant. If your diet is low in iodine, your child will also have low thyroid hormone levels at birth.

A child is at risk for congenital hypothyroidism if they have:

• A chromosomal disorder, such as Down syndrome, Williams syndrome, or Turner syndrome.
• An autoimmune disorder, such as type 1 diabetes or celiac disease, or a disease involving several hormone deficiencies, such as pseudohypoparathyroidism.
• Certain genetic conditions that may be hereditary.
• Injury to the thyroid gland.

Babies born prematurely whose thyroid and pituitary glands have not yet sufficiently developed are also at risk.

A newborn baby may have no symptoms at first. Often symptoms begin over the first few months and can include:

• Yellowing of the skin and eyes (jaundice).
• Lethargy.
• Feeding problems.
• Large fontanelle (the soft spot on top of a baby's head).
• Dry skin.
• A hoarse-sounding cry.
• Low appetite.
• Bellybutton that sticks out too far (umbilical hernia).
• Constipation.
• Slow bone growth.
• Weak muscles.
• Lack of energy.
• A puffy face.
• A large tongue.

Symptoms can vary with each child.

By law, all newborns born in United States hospitals are screened in the first few days of life for serious diseases. The testing is done with a few drops of blood taken from the baby's heel. One of the tests is for thyroid function. The test measures the amounts of hormones from the thyroid. It also measures the amounts of hormones that tell the thyroid to make more hormones. Your baby's doctor may also advise an imaging test of the thyroid gland. Babies born prematurely may need to have the newborn screening tests repeated a few weeks after birth to determine if their thyroid gland has continued to mature.

Congenital hypothyroidism is most often treated by giving a child synthetic thyroid hormones every day. It's important to start treatment even if your child has no symptoms. A delay in treatment can cause permanent learning problems and slow growth. Your child will likely need to take these for several years, and possibly for life. The length of time will depend on the results of testing and keeping track. In some cases, the thyroid gland may start working again. This may happen by age 3. The thyroid gland will be tested over time with blood tests. This can show if the thyroid starts working on its own. Your child's growth and development will also be tracked over time.

Congenital hypothyroidism can affect a child's normal growth and development. This includes sexual development. If untreated, the condition can also lead to:

• Low red blood cell levels in the blood (anemia).
• Low body temperature.
• Heart failure.
• Severe mental disabilities.

Congenital hypothyroidism can affect a child's normal growth and development. It's important for a child to continue treatment. This will help make sure a child reaches their normal adult height. Some children don't need to continue treatment into adulthood. Work with your child's doctors to create an ongoing plan to manage your child's condition.

Contact your child's doctor if you're concerned about your child's growth, or if your child has any signs of congenital hypothyroidism. Also contact the doctor if you have any questions about your child's medicine. Always check with your child's doctor or pharmacist about medicine interactions before using any new prescription or over-the-counter medicines, vitamins, or supplements.

• When the thyroid gland doesn't make enough thyroid hormone, it's called hypothyroidism. Congenital hypothyroidism is when the disorder is present in a baby at birth.
• Slow growth, lack of activity, and poor performance in school can be signs that your child does not have enough thyroid hormone.
• The most common cause is failure of the thyroid gland to grow during pregnancy, or it's located in an abnormal place in the neck.
• Treatment may include taking thyroid hormones to increase the level of hormones in the body.
• Congenital hypothyroidism can affect a child's normal growth and development.
• It's important for a child to continue treatment as directed. This will help make sure that a child reaches their normal adult height.

Tips to help you get the most from a visit to your child's doctor:

• Know the reason for the visit and what you want to happen.
• Before your visit, write down questions you want answered.
• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you for your child.
• Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.
• Ask if your child's condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if your child does not take the medicine or have the test or procedure.
• If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your child's doctor after office hours. This is important if your child becomes ill and you have questions or need advice.