Congenital Hypothyroidism

Congenital hypothyroidism is a condition found in newborns. When a baby has this condition, his/her thyroid gland is not making enough hormones for the brain and body to grow and develop.

The thyroid gland is located in the neck and is shaped like a butterfly. The thyroid gland makes many hormones that are important for growth and development. The hormones are called thyroxin (T4) and triiodothyronine (T3). These hormones are also important for energy and for the heart, liver, kidneys and skin. The brain makes a hormone called thyroid-stimulating hormone (TSH). TSH tells the thyroid gland how much T4 and T3 to make. When a child’s TSH is too high, the brain is working hard to tell the thyroid to make more T4 and T3. Sometimes the thyroid gland doesn’t make enough hormone no matter how hard the brain works. This is known as hypothyroidism.

There are many causes of congenital hypothyroidism. A baby can be born without a thyroid gland, the thyroid gland may be in the wrong place or the gland may not work correctly.

Congenital hypothyroidism can have little or no symptoms. If your baby has symptoms, he or she may have:

  • Problems sleeping
  • Problems feeding
  • Problems breathing
  • Constipation
  • Yellowing skin
  • Poor temperature control

All babies are tested for this condition within the first week of life. When a newborn screening (blood test) shows values that are not normal, your doctor may suspect hypothyroidism.

Congenital hypothyroidism can be easily treated with a daily medicine. The medication replaces the T4 that your child’s thyroid gland is unable to make. It is very important to make sure your child gets his/her medicine every day at about the same time. Children who do not take medicine to treat his/her hypothyroidism will have trouble growing and can develop mental retardation. Most children take this medication for life.

The medicine can be given with small amounts of formula or food. You may break the tablets in half or crush them to make it easier for your child to take.

The doctor will want to see you frequently during the first year to check on growth and development. Your doctor may want to see you as often as once a month. Sometimes the medicine dose will need to be changed. Blood draws during these visits will help your doctor make sure the medication dose is correct. Never change a medicine dose on your own. Once your child starts taking the medicine, there are symptoms to watch for that can help your doctor treat your child with the correct dose of medication.

Your child’s dose may be too high if he/she has:

  • Trouble sleeping
  • Shaking (tremors)
  • Weight loss
  • Irritability
  • Diarrhea
  • Excessive hunger

Your child’s dose may be too low if he/she:

  • Is sleeping too much
  • Has constipation
  • Has cold, dry skin
  • Has gained weight too quickly
  • Has low energy/activity level

Some infants will sleep less and seem more irritable after starting on thyroid medicine. This may mean that your baby has more energy and is a normal reaction to the medicine. A baby who has hypothyroidism and is not on medicine does not have as much energy as a baby who has hypothyroidism and is on medication.

It is important to make sure your child stays on the same brand of thyroid medicine. There are very small differences between brands of thyroid medicine that might affect your child’s labs and the way he/she feels. Please notify your nurse or doctor if your pharmacy changes brands of thyroid medication.