Congenital hypothyroidism is treated with thyroid medication only. There are many thyroid medications. At the hand of a good doctor almost all the thyroid medications Will control the thyroid. Thyroid hormone is very important for growth and development. For children less than 3 years thyroid is the principal hormone for the neurodevelopment of the brain.
Thyroid hormone need to be given at an optimum dose as to keep the TSH at the lower end of normal.TSH between 0.5-1.5 ideally. Of course we are talking about the 90% of children with primary congenital hypothyroidism not central hypothyroidism.