Neonatal hypothyroidism, or neonatal hypothyroidism, refers to the insufficient secretion of thyroid hormone in newborns, and its causes include primary congenital hypothyroidism and secondary, temporary hypothyroidism, so neonatal hypothyroidism is not necessarily congenital hypothyroidism. Primary congenital hypothyroidism, i.e. congenital hypothyroidism, is most commonly seen in the absence, underdevelopment or ectopic thyroid gland, i.e. the thyroid gland stays at the abnormal thyroid site in the process of downstaging, resulting in an ectopic thyroid that has partially or completely lost its function. Neonatal hypothyroidism can also be seen secondary to hypothyroidism, such as pituitary and hypothalamic lesions, resulting in hypothyroidism. In addition, temporary hypothyroidism can also be seen in newborns, such as the mother’s thyroid disease during pregnancy or premature delivery, etc., which may lead to temporary immaturity of the thyroid gland of the newborn, resulting in temporary hypothyroidism. Hypothyroidism in newborns is not always congenital, the symptoms of hypothyroidism in newborns must be promptly consulted, the cause of the disease is clearly identified, and treatment is carried out under the guidance of the doctor.