Low thyroid hormone in children may affect the development, parents need to pay attention to it in time. Usually the thyroid hormone mainly includes thyroxine and triiodothyronine, and the indicator is reduced, it may be the performance of hypothyroidism, usually the patient can appear expression dull, memory loss, joint pain, fear of cold, dry skin and other symptoms, and some patients can also be manifested as thinning hair, hoarse voice, hearing impairment, loss of appetite, etc., affecting the growth and development of the child. And children with low thyroid hormone may also be congenital hypothyroidism. Patients often have symptoms such as delayed expulsion of meconium, hypersomnia, delayed resolution of jaundice, difficulty in feeding, etc. They may also have low intellectual development, impaired motor development, and delayed neurological reflexes, which may also affect the child’s development. Parents are advised to seek prompt medical attention if their children are found to have low thyroid hormone and take prompt treatment after the diagnosis is confirmed.