The newborn screen came back as abnormal. Your baby has congenital hypothyroid what does that mean?

You're told your baby's newborn screen has come back abnormal. You take your infant to the lab, for additional testing. They order thyroid tests. Thyroid tests? Why are they taking thyroid tests if the PKU came back as abnormal???

This was a scenario I personally lived through with my daughter, who is as of this writing 6 months old. I have been a pediatric nurse for more than 11 years, working in everything from NICU to ER, to critical care transport. This was my second daughter. Yet, in spite of all of that, I didn't know what to make of this information. Congenital hypothyroid? What is congenital hypothyroid? As I talked to my pediatric nurse friends, they didn't know what to make of it either. So, I am writing this in hopes that another mother or father who finds themselves going through the same thing can find information and comfort here.

The newborn screen - not just PKU. We call it the PKU test, we have labels on foods and drinks with warnings for people with PKU, but the newborn screen encompasses many other things, among them congenital hypothyroid, which is ironically more common than PKU. Why do we screen newborns for hypothyroid? Congenital ypothyroid is a preventable cause of mental retardation. The earlier it is caught, and thyroid replacement is started, the better the outcome.

No one knows what causes infants to be born with congenital hypothyroid. There are cases of families with multiple children with the disorder, suggesting there may be a genetic factor. However, these cases seem to be sporadic at best. We know that iodine deficiency in diet can cause thyroid deficiency, which is why salt here in the U.S., and I suspect in many other countries, is iodized. The vast majority of cases though have no known reason. What does this mean? If your child has hypothyroid, you did not do anything to cause it. So, if you have been blaming yourself, you can let it go.

What are the signs and symptoms of Congenital hypothyroid? The findings of children with hypothyroid, are also found in infants with no disease. Often the babies are born late, and large. Commonly you see umbilical hernia (a belly button that sticks out and can be pushed back in), large fontanels (soft spots), and a large protruding tongue (baby sticks out his / her tongue). Jaundice (yellow skin) that takes longer to go away is also common. As time progresses baby may not eat well, may gain or lose weight, may be floppy, may sleep excessively, may not grow in length as expected. As more time goes by brain development becomes affected. This is why we have newborn screening. This is also why once your doctor prescribes thyroid replacement for your baby you must fill it and give it every day as directed.

What additional tests will my baby receive / need? At a minimum, your baby will receive a blood test after receiving the abnormal results, and at regular intervals thereafter to ensure that the appropriate balance is maintained. My endocrinologist sees us every 3 months for the first year of life because of the rapid growth that takes place during that time period. Additional tests may be ordered. These can include ultrasounds, and other radiologic scans to determine if there is any functional thyroid tissue. You should talk with your doctor and discuss the risks and benefits of each of these exams. You should then make a decision together as to the necessity of each of these. I personally was prepared to agree to an ultrasound of the thyroid, but would have refused additional scans as I prefer not to subject my children to additional radiation unless necessary. There are many things for which I would agree to CT scans, xrays, MRIs, etc for my children because I believe them to be very useful. However, none of the options in this case would change my daughters treatment. As it happened, my endocrinologist did not recommend these.

How do we treat hypothyroidism? Just like adults who have hypothyroid, babies who are diagnosed have to take thyroid replacement every day. If you see an endocrinologist who does not specialize in children, consider asking for levoxyl. This is a brand name of thyroid replacement that dissolves exceptionally well in milk or water, making it easier to give. The generic is exceptionally difficult to mix. Be prepared to pay for the first prescription, usually about $30 as many insurance programs are not yet active for babies by the time you receive the diagnosis. It is very important not to wait, even a few days to start the medication. Also be prepared to tell the pharmacy that you want the brand name not the generic. The medicine should be mixed with a small amount of water or pumped breastmilk, and given with a bottle or oral syringe. It is generally not recommended that you give the thyroid medicine with infant formula, as it contains iron. You also should not mix it in a full bottle. The reason for this is that your baby may not take all of the bottle, and you will have no way to know how much medication was taken in.

Will my baby be ok? Babies who are started on medication quickly, and who are given their doses every day, and receive their follow up testing tend to do very well. So, give the medicine, every day, no matter what. Do not try to double up dosing as that will not make your infant any smarter. Instead it can cause hyperthyroid, which can also cause problems. Continue to take your baby to regular pediatrician visits, and get your baby vaccinated. The vaccines have no interaction with the thyroid medication, and your pediatrician can help you follow your baby's developmental milestones.

Will my baby have to take medicine forever? The answer to this is maybe. At 3 years of age it is generally recognized that your child's brain is developed enough to try going without medication. Some children will have started making enough of their own thyroid, others will not. If your child has not started making sufficient thyroid, then yes, your baby will have to take thyroid medication every day. Yet, that is such a small price to pay for keeping your baby healthy!