Over half the babies born with congenital hypothyroidism appear completely normal and have no symptoms at all. This is why it is so important that all children are tested at birth. Congenital hypothyroidism is normally diagnosed before a baby shows any definite signs of the condition.

Some babies with congenital hypothyroidism are sleepy and difficult to feed – although lots of babies have these symptoms without being hypothyroid! Other signs may include:

  • constipation
  • low muscle tone (floppiness)
  • cold extremities
  • slow growth

Some hypothyroid babies have prolonged jaundice after birth.

Although some children with congenital hypothyroidism have development problems, the likelihood of long-lasting effects on development is low. If your child is diagnosed with congenital hypothyroidism, the doctor will examine them very carefully to check for any other problems.