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Column originally published Jul 22, 2003

Congenital Hypothyroidism Needs Early Treatment With Thyroid Hormone

Question: Our daughter was born recently. She was a wonderful girl, but she slept a lot and it was hard for me to wake her up for nursing. When she was three-days-old, our doctor informed us that she has a condition called congenital hypothyroidism. We were told that she likely needs thyroid hormone supplement for the rest of her life. We were totally devastated to hear this news. We thought she was a perfectly healthy girl, other than being more sleepy. Since starting the thyroid hormone, she is more alert and wakes up every two to three hours to feed. Can you explain why this could happen to our otherwise perfectly normal baby?


Children with congenital hypothyroidism (CH) are born with little or no thyroid hormone. This hormone is normally produced by the thyroid gland, which is located in the middle part of the neck.

There are many known (and some unknown) causes of CH. Many children with CH do not have any detectable thyroid gland, while others have a small gland that is misplaced and doesn’t function properly. The end result is a lack of thyroid hormone production.

During a normal pregnancy, the thyroid gland of the foetus starts to produce thyroid hormone towards the end of first trimester (which is around 3rd and 4th month of pregnancy). The amount of thyroid hormone produced by the foetus gradually increased so that at birth, the thyroid hormone level is close to that of normal adults.

If the thyroid gland does not develop normally, little or no thyroid hormone is produced. Fortunately, the mother’s thyroid hormone can pass through the placenta to the foetus. The amount of thyroid hormone detected in newborns with CH is about 1/3 to ½ of normal. This small amount of thyroid hormone is enough to allow the foetus to grow normally throughout the pregnancy.

As a result, most children with CH appear completely normal at birth. There may be very subtle signs that are difficult to recognize by parents as well as physicians. The soft spot in the head (called anterior fontanelle) may be wider than normal. Sometimes there can be a hernia at the umbilicus. These babies are generally more sleepy, and wake up less often for feeding. Jaundice, which is normal in all newborns, can stay on for much longer than normal.

However, all of these signs and symptoms are subtle, and difficult to recognize. That is why before universal screening became available, almost all of these children were missed until several months of age, when parents start to notice that their babies cannot turn over or sit up like all other children.

Thyroid hormone is essential for every part of the body. In newborn babies, the brain develops rapidly during the first two years of life. Without adequate amount of thyroid hormone, the brain develops much more slowly. The tragic part is this: the delay is permanent. When the condition is finally recognized, and thyroid hormone replacement is started, every part of the body will improve, some almost completely. The damage to the brain’s development, however, is permanent. These children are mentally retarded and cannot catch up.

That is why universal screening for thyroid hormone deficiency in newborns is so important. This is carried out in North America as well as in many parts of the world. Most laboratories are able to report abnormal results within one or two days after the test is done.

Because screening test has been available for several decades, many babies with CH have been treated successfully, beginning usually a few days after birth. The earlier treatment is started, the better it is for the baby.

Once treatment is initiated, it is most important to monitor the baby with regular blood tests. Because of low thyroid hormone level, another hormone called TSH (thyroid-stimulating hormone) is produced in large quantities, trying to stimulate the thyroid gland, which is either absent or not functioning properly. By monitoring the thyroid hormone and TSH levels, doctors can keep the child under the best control, without risking too little or too much medicine.

Most children with CH have to take thyroid hormone supplement for life. This seems like a serious blow to you, having delivered a normal-looking baby, and then feel like being condemned to life-long medicine. If one looks at how a tiny thyroid hormone pill can change a child from mental retardation to normal health (and perfectly normal intelligence), one should marvel at the advance of medical technology permitting this to happen.

A thyroid pill is far better than insulin injections and blood tests that are required for diabetic children. One can look at whether a person’s life is half full or half empty. I certainly believe your daughter’s life is much more than half full!

I hope the information that I have provided here is helpful for you to understand your daughter’s condition. Hopefully you can take consolation that her problem was recognized so early. If her thyroid hormone is adjusted properly, she will develop normally like any other child, and can achieve her full potential.