The size of the head is also the size of the skull is related to hereditary factors, acquired nutritional status, and whether there is a disease effect. If it does not affect the development of the brain, you can not be overly concerned. The first thing is to rule out whether the head circumference is determined by genetic factors, you can first observe whether the parents’ elders have small head circumference; secondly, if excessive calcium supplementation before the age of one, prompting the premature closure of the fontanelle of the skull, will limit the growth of head circumference; there is also the need to rule out whether it is caused by related diseases.