The Laboratory Features of Congenital Hypothyroidism and Approach to Therapy.

Congenital hypothyroidism (CH) is one of the most common preventable causes of intellectual disability. Thyroid hormone is required for normal brain development, but neonates with CH typically appear healthy at birth, which leads to delays in diagnosis and treatment. In developed countries, newborn screening programs have led to earlier diagnosis and treatment of CH, resulting in improved neurodevelopmental outcomes. Neonates with an abnormal newborn screen require prompt confirmatory serum thyroid function tests and treatment with thyroid hormone. Further evaluation for the etiology of CH should not delay treatment decisions.