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California Newborn Screening Program

Primary Congenital Hypothyroidism

Infants with congenital hypothyroidism produce inadequate amounts of thyroid hormone. This hormone is essential for normal brain development, growth, and metabolism. By three months of age, there is documented irreversible mental retardation and significant clinical symptoms in many untreated affected infants. Signs and symptoms include:

  • prolonged neonatal jaundice
  • failure to thrive
  • lethargy
  • poor muscle tone
  • feeding problems
  • constipation
  • coarse facial features, thick tongue, depressed nasal bridge
  • distended abdomen
  • umbilical hernia
  • hoarse cry

In 5-10% of infants with severe disease, such signs and symptoms may be detected during the neonatal period. It is important to diagnose congenital hypothyroidism as soon as possible since early onset of therapy will avert irreversible mental retardation and other organic sequelae.

L-thyroxine is given orally on a daily basis, with the dosage based on age, weight, and response to therapy.

Congenital hypothyroidism is subdivided into primary, secondary, tertiary, and transient hypothyroidism. The Newborn Screening Program is limited to detecting primary congenital hypothyroidism.

Parents' Guide to Primary Congential Hypothyroidism (PDF, English)  ...Spanish (PDF)

Last modified on: 8/24/2010 3:24 PM