Increased head circumference

Alternative names

Increased head circumference is present when the measured distance around the widest part of the skull is larger than expected for the age and background of the child.

As a rule of thumb, 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 intracranial pressure (pressure within the head, usually caused by swelling of the brain or accumulation of cerebrospinal fluid within ventricles) often accompanies increased head circumference. Symptoms associated with this include vomiting, eyes deviating downward, and irritability.

See also bulging fontanelles.

Common Causes

  • Hydrocephalus (congenital, post-traumatic, or obstructive)  
  • Canavan disease  
  • Hurler syndrome  
  • Morquio syndrome  
  • Benign familial macrocephaly (family tendency toward large head size)  
  • Intracranial bleeding

Call your health care provider if
Macrocephaly is usually discovered by the health care provider during a routine well-baby exam.

What to expect at your health care provider’s office
The medical history will be obtained and a physical examination performed.

Medical history questions documenting increased head circumference in detail may include:

  • Time pattern       o When did you first notice that the baby’s head seemed large?       o Does the baby’s head size seem to be increasing faster in proportion to the growth of the body?  
  • Location       o Does the head seem larger all over?       o Is the head growing more in a front-to-back pattern or in a side-to-side pattern?  
  • Other       o What other symptoms are also present (especially changes in brain or nervous system functions)?

Physical examination may include repeated measurements of the head circumference over a period of time to confirm that the head circumference is significantly increased. However, in some cases a single measurement is sufficient to confirm a significant increase.

Diagnostic tests may vary depending on the suspected cause, but often include:

  • Head x-ray  
  • Head CT scan

After seeing your health care provider:
If a diagnosis was made by your health care provider of cause of increased head circumference, you may want to note that diagnosis in your personal medical record. You may also want to document your own measurements of the head circumference.

Johns Hopkins patient information

Last revised: December 3, 2012
by Gevorg A. Poghosian, Ph.D.

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All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.