Though rare, newborn thyroid conditions can affect baby’s growth and development. Newborn screening is essential for early detection and intervention.
Do you know that the small amount of blood that baby’s nurse draws also screens for problems your baby may have with their thyroid? Congenital (meaning born with the problem or condition) thyroid problems need to be caught and treated early.
The thyroid and its role
The thyroid is a small, butterfly-shaped gland on the front of the neck. It sends hormones made by the brain’s pituitary gland throughout your body to regulate bone and brain growth, sexual development and chemical reactions that fuel metabolism. Your heart rate, blood sugar and temperature are all affected by the amount of thyroid hormone in your body.
The pituitary gland produces thyroid stimulating hormone, TSH, which tells your thyroid to make and release the thyroid hormones into your bloodstream. Measuring TSH in baby’s blood at birth helps determine if baby has either of the most common thyroid conditions.
Hyperthyroidism—an overactive thyroid—is an extremely rare newborn thyroid condition and usually happens when mom also has it. It affects boys and girls equally and happens in about 1 in every 25,000 births.
Hyperthyroidism can cause problems including small for gestational age babies, premature birth, small head size, fast heart rate, irritability, an enlargement of the thyroid, and possibly eyes that appear to bulge out, called exophthalmos.
If your baby has hyperthyroidism, they may be prescribed an anti-thyroid drug such as methimazole for the first few months of life. Most infants recover by the end of the third month making early treatment important.
If baby’s thyroid is underactive (hypothyroidism), baby’s thyroid gland may not be fully formed. Other causes include a pituitary gland that doesn’t send enough signals to the thyroid, or thyroid hormones that don’t work properly. Most babies don’t initially have symptoms. This happens in about 1 in every 3,000-4,000 babies born in the US. Girls have this problem 2 times more often than boys.
When hypothyroidism is more severe, baby may have a puffy face, thick tongue, jaundice, problems feeding, constipation, poor muscle tone, low temperature, large fontanelles or “soft spots” on the head and dry skin.
Additional blood tests can confirm congenital hypothyroidism if it’s suspected after the first screen. It’s important to start treatment for this newborn thyroid condition even before the second blood test results are confirmed. Most of the effects of hypothyroidism are reversible with fast and constant treatment in the first 2 weeks of life.
When not treated quickly, infants with hypothyroidism have a higher-than-average risk of other congenital problems including heart problems, poor growth, hearing problems and severe intellectual disability.