The thyroid is a gland in the lower neck. It makes hormones that regulate growth, brain development, and metabolism. Hypothyroidism is a low or absent production of these hormones. Congenital means the conditions is present since birth.

The Thyroid Gland

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If this condition is not treated it can cause damage to the brain. This can lead to mental retardation and abnormal growth.

Causes and Risks

In most cases, the cause is unknown.

The most common known cause is abnormal development of the thyroid gland. A small percentage of cases are inherited.

Other causes may include:

  • Medication during pregnancy, such as radioactive iodine therapy
  • Maternal autoimmune disease
  • Too much iodine during pregnancy
  • Inborn error of metabolism

Some babies are born early (before 40 weeks). This may cause a temporary shortage in the thyroid hormones.


Symptoms or signs take time to develop. The symptoms of Congenital hypothyroidism may include the following:

  • Puffy face
  • Coarse facial features
  • Dull look
  • Thick protruding tongue
  • Poor feeding
  • Choking episodes
  • Constipation or reduced stooling
  • Jaundice prolonged
  • Short stature
  • Swollen, protuberant belly button
  • Decreased activity
  • Sleeps a lot
  • Rarely cries or hoarse cry
  • Dry brittle hair; low hairline
  • Poor muscle tone
  • Cool and pale skin
  • Goiter (enlarged thyroid)
  • Birth defects (eg, heart valve abnormality)
  • Poor weight gain due to poor appetite
  • Poor growth
  • Difficult breathing
  • Slow pulse
  • Low temperature
  • Swollen hands, feet and genitals


At birth, most infants are screened for this condition. Tests may include the following:

  • Measurement of free (unbound) thyroxine (T4) levels in the blood
  • Measurement of thyroid stimulating hormone (TSH) in the blood
  • Thyroid scan (technetium)
  • Nuclear imaging (scintigraphy) may help determine the cause of congenital hypothyroidism, which can guide treatment and prognosis


The outcome is best if the condition is caught early. It is important to start treatment before the brain and nervous system are fully developed. If treatment is given early, it could prevent damage.

Left untreated, the condition can lead mental and growth retardation.

Hormone replacement therapy is often done with the hormone thyroxine, given in one of the following forms:

The tablets should be given at least 30 minutes before a meal or feeding.

Once medication starts, the levels of thyroid hormones are checked often. This will help to keep the values within normal range. If values are kept within a normal range, there are no side effects or complications.


Most cases can not be prevented. The following are some things the mother can do during pregnancy to reduce the risk:

  • Mothers should not have radioactive iodine treatment or use iodine as antiseptic
  • Mothers should consume enough, but not too much iodine