Congenital deficiency of thyroid hormone


Congenital deficiency of thyroid hormone is an uncommon disease found in about one in three thousand newborn babies. It is also called congenital hypothyroidism. By discovering the disease early, the child can receive treatment before they get symptoms.

There are several causes of congenital thyroid hormone deficiency. In almost all children with congenital hypothyroidism, the thyroid gland has not been formed and developed properly during fetal life. Some children lack the thyroid completely, while others have a thyroid that is smaller than it should be. Other more rare causes are congenital changes in thyroid hormone formation.

In some children, the deficiency of thyroid hormone is transient, while in others it remains throughout life. Usually there is no explanation as to why the thyroid gland has not developed properly or why the production of thyroid hormone is not working. It appears that some of the parents also have congenital thyroid hormone deficiency, but it is very uncommon.

Symptoms of congenital deficiency of thyroid hormone

During pregnancy, the baby receives enough thyroid hormone from her mother via the placenta. Therefore, the baby usually has no signs of thyroid hormone deficiency when born. Also, no symptoms develop if the child is treated with thyroid hormone early.

It takes quite a long time before any symptoms are noticed if the child has not received treatment. The severity of the symptoms depends on the severity of the hormone deficiency. The deficiency of thyroid hormones can vary from child to child.

Signs of hypothyroidism may be these:

  • The child does not want to eat.
  • The child sucks badly.
  • The child has a low body temperature.
  • The child has moderate jaundice which does not bring with it.
  • The child has a small horse scream.
  • The child is tired and has an increased need for sleep.

Some newborns with hypothyroidism are very quiet.

The large fontanelle, that is, the space between the head bones, can be extra-large. Many children with hypothyroidism get a so-called umbilical hernia if the diagnosis and treatment are delayed. The baby’s development is also delayed if thyroid hormone therapy is not started early. 


A blood test is taken on all newborn babies when they are two days old. The test checks, among other things, whether the child has a congenital deficiency of thyroid hormone. The child is called directly to a pediatrician if the blood test indicates that they have a deficiency of thyroid hormone. At the pediatrician, the child is examined and new blood samples are taken. 

Treatment for congenital deficiency of thyroid hormone

Thyroid hormone therapy is started immediately at the first visit to the pediatrician if the suspicion of congenital thyroid hormone deficiency in the first blood test is high. If the suspicion is not the same, wait for the answers to the blood samples taken at the first doctor’s visit before possibly starting treatment.

The treatment consists of thyroid hormone that is given in tablet form with any of the medicines Levaxin or Euthyrox. The tablets can be crushed and given with some breast milk or milk replacement. Treatment should begin during the first two weeks of life so that brain development is not affected.

Check after two weeks

When the child has been treated for two weeks, a check is usually made. Then the child is examined by a pediatrician and blood tests are taken to measure the levels of thyroid-stimulating hormone TSH and thyroid hormone T4. The sample is taken from a blood vessel in the child’s hand or foot. The baby can breastfeed or get some sugar solution in the mouth to relieve the discomfort of the sting.

Sometimes the hormone dose may need to be changed. During the child’s first months, relatively close checks are usually made. Thereafter, checks are made approximately every three months during the first two years of life. 

Most children with congenital thyroid hormone deficiency need to continue taking medication throughout their lives. In some children, an attempt can be made to end thyroid hormone therapy when the children are three to four years old and the brain is not dependent on thyroid hormone for its development anymore.

How is the child’s development affected?

The congenital deficiency of the thyroid hormone usually does not cause any problems or complications if the child is treated early. Most children become symptom-free and develop as they should if the dosage of the drug is correct and the treatment is done properly. 

This is how the thyroid gland works

The thyroid gland is located on the front of the neck just below the larynx. It is also called the thyroid.

The gland forms two hormones Trijodtyronin (T3) and Thyroxine (T4) which have several important functions in the body. Hormones control, among other things, metabolism and are necessary for the child to grow well. They also play a very important role in brain development during the first two to three years of life.

The thyroid function is in turn controlled by the hormone TSH, that is, a thyroid-stimulating hormone that is formed by the pituitary gland that is located in the brain.

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