The baby’s head size may be caused by heredity, or considered to be caused by rickets, pediatric hydrocephalus and other diseases. 1. Heredity: due to the existence of individual differences in babies, some babies due to heredity, there can be congenital head circumference of the skeleton larger, manifested in the baby head. 2. Rickets: rickets is due to a variety of factors leading to vitamin D deficiency in the body, causing calcium and phosphorus metabolism malfunction in the whole body, resulting in the epiphysis of the long bones and bone tissue mineralization is not complete. Affected children will have an increased head circumference, the appearance of the skull is square, manifested in the baby’s head is large. 3. Pediatric hydrocephalus: Pediatric hydrocephalus may be caused by intrauterine infection during pregnancy, prematurity, excessive production of cerebrospinal fluid, and impaired absorption of cerebrospinal fluid. Affected children may have symptoms such as irritability, enlarged head, and excessive increase in head circumference. There may be other reasons for the baby’s large head, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment under the guidance of the doctor.