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Newborn and Infant Care

Head size above the 100th %



AT MY SONS 2 MONTH CHECKUP ( he was actually 10 weeks) HIS HEAD SIZE MEASURED ABOVE THE 100TH % his head circumference was 17.75 inches. he is at the 95% for weight and 65% for height. he is now 3 mos. old and does not have much head control. I have measured and in 3 weeks his head has grown slightly over 1/4 inch. should i be concerned or just see what happens at his next doctor appt.?


There are several factors which may contribute to increased head size.

There can be some "operator error", that is, slightly different technique from person to person, or how cooperative the child is with the measurement. Or was the measurement recorded properly?

There can be a family predisposition to large head size (macrocephaly). If there are family members with larger than usual heads, chances are that the infant will have a larger than average head. At times this type of occurrence is related to familial or genetic causes of increased head size. Your healthcare provider is/will be looking for other physical or developmental clues for this type of enlarged head size.

Then, there can be a child whose head is growing too fast due to spinal fluid backing up in the ventricles (chambers) of the brain; a condition known as hydrocephalus. In general, the infant brain grows at a rate of about 2 cm (about an inch) a month for the first three months, about 1 cm (1/2 inch) a month from 3-6 months, and 0.5 cm (1/4 inch) per month until a year of age. Your son seems to be within these ranges since his last visit.

Having full head control is a skill which most infants acquire by age 4 months. Having daily periods of observed "tummy time" will help reach this goal by allowing the child to use or exercise the muscles in the chest, forearms, and neck which are needed to control the head.

I cannot say you should not be concerned about this or any other factor regarding your child, as his mother, you have that right. However, a head circumference >100% on the head circumference charts while unusual, without associated findings may very well deserve only monitoring at this point.

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Response by:

Sarah Sauntry, RN, MS, CPNP-PC
Assistant Professor of Clinical Nursing
College of Nursing
University of Cincinnati