Congenital hypothyroidism is a clinical syndrome caused by defects in the synthesis, secretion or action of thyroid hormones due to congenital causes. Generally speaking, congenital hypothyroidism has many causes, which are mainly classified as central and peripheral: 1. Central: Central hypothyroidism is mainly caused by a decrease in the secretion of thyrotropin-releasing hormone by the hypothalamus or a decrease in thyrotropin secretion by the pituitary gland due to various reasons; 2. In addition, a small number of patients have clinical hypothyroidism mainly due to insensitivity or resistance of tissues and organs to thyroid hormones. In clinical practice, the incidence of congenital hypothyroidism is increasing and may be caused by viral infections in early pregnancy, peripheral radiation damage, or early medication misuse.