Targeted Levothyroxine Dosing in Infants With Congenital Hypothyroidism

This is a clinical study comparing targeted levothyroxine dosing based on thyroid anatomy as visualized on ultrasound (normal vs. ectopic/sublingual vs. athyreosis) to empiric levothyroxine dosing in infants with congenital hypothyroidism. Patients enrolled in the study for targeted dosing will be compared to controls obtained by retrospective chart review. The main outcome is to determine if there is a difference in the frequency of over-treatment and under-treatment during the first 6 months of therapy.