An infant’s fontanel usually closes around one and a half years of age and no later than two years of age, but the exact time varies because of some individual differences.
The size of the fontanel and the time of closure can assess the growth and development of the skull. The fontanel is about 1 to 2 cm at birth and increases in size as the skull grows. However, it slowly decreases in size around 6 months of age and usually closes around 1.5 years of age, or as late as 2 years of age in some infants.
It is important to note that when the brain is underdeveloped, the head circumference will develop smaller and the fontanel will close earlier. In infants with hypothyroidism and severe calcium deficiency, fontanel closure will be delayed and require prompt calcium intervention. When washing the baby’s hair, parents should pay attention to the fact that the fingers should only gently wash the fontanel flat and should not be pressed or scratched.
It is recommended to observe the fontanel for any abnormal changes, and go to the hospital as soon as possible if the fontanel closes early or late.