Increased head circumference is when the measured distance around the widest part of the skull is larger than expected for the child's age and background.
A newborn's head is usually about 2 centimeters larger than the chest size. Between 6 months and 2 years, both measurements are about equal. After 2 years, the chest size becomes larger than the head.
A series of measurements over time that show an increased rate of head growth often can provide more valuable information than a single measurement that is larger than expected.
Increased pressure in the head (increased intracranial pressure) often accompanies increased head circumference. Symptoms associated with this condition include:
See also: Bulging fontanelles
The health care provider usually finds macrocephaly during a routine well-baby exam.
The health care provider will take a medical history and will perform a physical examination.
Medical history questions may include:
Physical examination may include repeated measurements of the head circumference over a period of time to confirm that the head circumference is significantly increased. In some cases a single measurement is enough to confirm a significant increase.
Diagnostic tests may vary depending on the suspected cause, but often include:
After seeing your health care provider:
If your health care provider diagnosed the cause of increased head circumference, you may want to note that diagnosis in your personal medical record.