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Newborn and Infant Care

Large Head Circumference



I have a baby girl who is now 18 months old. She has had issues with head size among other things but this is the most concerning. Her head circumference is 51.5cms her height is 76cms and her weight is 11kgs, when this information is plotted onto a graph nothing seems to match up.

Is this a big concern?


I want to compliment you on your understanding of your child's growth measurements. Indeed they do not match well one with another. Her weight is at the 50th percentile, her length is at the 10th percentile and her head circumference is over the 95th percentile on the 2000 CDC growth charts for girls birth to 36 months of age. Of course this is presuming that all of the measurements were obtained using correct techniques. These are well described on the http://www.cdc.gov/ website. I hope that with such wide differences among her measurement percentiles were retaken carefully and verified. if not, I would ask that that they be retaken and re-plotted on the growth chart to be certain all are correct.

Now to the question about should you be concerned. You also said that your daughter's large head size is "one among other things." Those "other things," if they are developmental and/ or behavioral in nature, may be signaling that there really is a problem in her central nervous system. On the other hand, large heads do run in families and the underlying brain is absolutely normal. The skull is larger and there is more fluid cushioning the brain but there is nothing wrong with brain growth and function.

The most common causes of a large head that indicate developmental problems are autism and Fragile-X syndrome. Many children with autism do have larger than normal head sizes and it is recommended that their head circumference be followed through 6 years of age, whereas we only do that through 2 years of age ordinarily. Fragile X syndrome occurs in both boys and girls and is a differential diagnosis for autism. Although children with Fragile X do share common developmental deficits with children who have autism, the two conditions are not identical. Many centers caring for children with autism test for Fragile X syndrome to make sure of the diagnosis.

Because the brain is so flexible in the first three years of life, it is critical to identify developmental problems as soon as possible so that children can receive special therapies to build their developmental skills and help them be as ready for school as possible. Access to special services hinges on the child receiving a diagnosis. On the other hand, learning that all is well is a huge relief and means you can stop worrying about possible problems.

So I do highly recommend that you discuss with your child's doctor the need for a referral for your daughter to a pediatric neurologist or a developmental and behavioral specialist. These specialists often work together and will make sure all of the correct testing and exams are done and your family referred to the best health care services for your child, if anything special is needed for her.

I hope that this information proves helpful to you and that all is well with your child.

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Response by:

Mary M Gottesman, PhD, RN, CPNP, FAAN Mary M Gottesman, PhD, RN, CPNP, FAAN
Professor of Clinical Nursing
College of Nursing
The Ohio State University