Newborn babies who are unable to make enough thyroid hormone have congenital hypothyroidism, also known as neonatal hypothyroidism, meaning they are born with an underactive or absent thyroid gland. If the condition is not found and treated, it can result in irreversible neurological problems and poor growth. The good news is that early diagnosis and proper treatment can prevent these problems. In most cases, the condition is permanent and your child will need lifelong treatment. About 1 in every 2,000 to 4,000 babies is born with congenital hypothyroidism. It is twice as common in girls as in boys.
The most common causes are:
These abnormalities are not inherited from the parents.
Other possible causes include:
Many babies with congenital hypothyroidism appear normal at birth or for several months after birth. But others may have these signs and symptoms:
Thyroid hormone deficiency can also occur in older babies or young children, even if test results at birth were normal. If your child shows signs and symptoms of hypothyroidism, contact your doctor right away.
Most newborns in the United States are tested a few days after birth for congenital hypothyroidism as part of standard screening tests. These tests detect almost all cases of congenital hypothyroidism. Doctors check blood levels of:
Low levels of T4 and high levels of TSH suggest a diagnosis of congenital hypothyroidism. Doctors also might do a thyroid scan or an ultrasound exam to look at the size and location of the thyroid or to find out if it is missing altogether.
Every day, you will give a replacement form of thyroid hormone to your baby to substitute the missing thyroid hormone. You"ll crush the hormone pill and mix it with a small amount of water, breast milk, or formula. Do not mix it with soy protein-based formulas, because they interfere with absorption of thyroid hormone. Then you'll give it to your baby by mouth, using a medicine dropper, syringe, or open nipple. Treatment begins as soon after birth as possible. In most cases, your child will need to take daily thyroid hormone throughout life.
Talk with your doctor about how often to have follow-ups. The doctor will recommend blood tests to check your child's hormone levels regularly, including one month after any dose change, to make sure your child is getting the right amount of hormone. The doctor also will check your child's growth and brain development.
The Hormone Health Network is the public education affiliate of the Endocrine Society dedicated to helping both patients and doctors find information on the prevention, treatment and cure of hormone-related conditions.
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