Why Is the Head Disproportionately Large During Infancy?

Macrocephaly is usually a symptom of other conditions. Benign familial macrocephaly is an inherited condition. It happens in families predisposed to having larger heads. Sometimes there is a problem with the brain, such as hydrocephalus or excess fluid.

Why are infants heads so big?

An infant with macrocephaly will have a larger head than most other infants of the same age and sex. In many cases, this condition is benign or harmless. In other cases, it may indicate an underlying medical condition, such as a genetic syndrome or a brain tumor.

Does head size increase with age?

It increases by 17% during the first 3 months of life, and by 25% at 6 months of age. It increases by about 1 inch during the 2nd year, and during the 3rd through the 5th year head circumference increases by about one-half inch per year.