Why Is Head Circumference Measured?
In babies, head circumference (the distance around the largest part of the head) can provide clues about brain development. If a baby’s head is bigger or smaller than most other kids’, or the head circumference stops increasing or increases quickly, it may indicate a problem. For example, an unusually large head may be a sign of hydrocephalus, a buildup of fluid inside the brain. A head that’s smaller than average may be a sign that the brain is not developing properly or has stopped growing.