General baby fontanel in 6 months of age around the gradual ossification and become smaller, the latest in 2 years old closed. If the baby is one and a half years old has not closed, if there is no other abnormalities can be observed for a period of time, but this situation is mostly caused by malnutrition, their own calcium metabolism abnormality, so the need for timely supplementation of nutrients and calcium supplements, the daily routine can be appropriate sunshine. 1. Observe for a period of time: some babies because of their own development problems, resulting in one and a half years old fontanel has not closed, but if there are no other abnormal signs and symptoms, you can continue to observe for a period of time. 2. Timely supplementation of nutrition: lack of nutrients in the body can also lead to the baby fontanel is not closed in time, the diet should be supplemented with enough protein and calories, such as meat, eggs, milk, etc., to promote the body’s absorption of nutrients. If necessary, you also need to give your baby vitamin D and calcium supplements in time to prevent rickets. 3. Appropriate sunbathing: you can give your baby 10-15 minutes of sunbathing once a day to promote the baby’s absorption of calcium, but be sure to choose the sun’s ultraviolet rays are not too strong in the time period, so as not to cause unnecessary damage to the child’s skin. If the one and a half year old baby fontanel is not closed and there is an abnormal increase in head circumference, you need to go to the hospital in a timely manner to rule out hydrocephalus, it is recommended that there are abnormalities must be timely medical care.