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Inherited Disorders and Birth Defects

Small head size-Very concerned



My daughter was born 10 days early with the following measurements: Weight 6 lbs, 6 oz; Length 19.5 in, and HC 32 cm. Based on my reading of the CDC growth charts, her head circumference was in the 3rd percentile. When I asked my pediatrician, they said her head is in the 10th percentile and they are not worried about it. At 2.5 weeks, she weighed seven pounds, was twenty inches, and HC was 34.5 cm. I am very concerned as I read an article that said that less than the fifth percentile at birth is a marker for developmental delays. Also her head at almost one month still looks coneshaped. Should I be concerned and should I seek a second opinion regarding her head size? I am very worried as neither my husband or I appear to have small heads. (I have measured mine between 55-55.5. cm).


Depending on the specific growth charts used, the percentiles can vary some - from the 3rd% to the 5th% up to the 10th%. The growth curves have changed over the years and may be slightly different depending on how the growth curve was originally constructed from data collected nationwide.

A head circumference between the 3rd and 97th percentiles is considered to be within the normal range. Other factors that might influence the measurement were how carefully the initial measurement was taken at birth as well as your daughter's head shape. If she has a lot of molding (cone shaped) it could change the measurement taken at birth a bit.

The more important measurement is one that shows the head circumference is growing, which in your case seems to be what is happening. A head circumference of 34.5 cm at 2.5 weeks is about the 25th percentile. If your daughter's head circumference were to stop growing or slow down so that the measurement drops back down to or below the 3rd percentile, then it would be very appropriate to have her evaluated. While a small head circumference can be associated with developmental delays, there are almost always other problems present or the head circumference does not increase in size as it should.

If you continue to be concerned, you may want to get a second opinion from another pediatrician.

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Response by:

Anne   Matthews, RN, PhD Anne Matthews, RN, PhD
Associate Professor of Genetics
School of Medicine
Case Western Reserve University