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Newborn and Infant Care

Small head circumference

03/20/2006

Question:

We are adopting a baby girl from Guatemala. She is 3 months old and weighs ~13 lbs, height is 39 cm and head circumference is 38 cm. We were told her head circumference is in the 10th percentil for age and `may be concerning`.

What would a small head circumference indicate if the rest of her body is growing at a normal pace? Should we be concerned with mental retardation or other problem with the brain?

Thanks for your help!

Answer:

You are asking a very good question. Plotting her weight on a growth chart shows her weight to be in the 75th percentile for a full term infant. This means that out of 100 3-month-old infant girls, she weighs more than 75 of them. I feel quite certain that her length must be incorrect because it plots out on the growth chart as below that of a term newborn. A head circumference at the 10th percentile means that out of 100 3-month-old infant girls, there are only 10 girls with head circumferences smaller than the baby you are thinking of adopting.

As evidence of normal growth we look for a healthy, term infant's weight, length, and head circumference to all be in approximately the same percentiles. For this baby girl there is a strong mismatch between her weight at the 75th percentile and her head circumference at the 10th percentile. It would be a great idea to double check her length with the adoption agency. I would be happy to plot it on a growth chart and tell you what it means.

A small head circumference can mean several things. Her biological parents may tend to have smaller than average (the 50th percentile) head sizes, so that the baby's head measurements simply reflect her genetic heritage. However, it may also mean that her brain is not growing well during this crucial period of the brain growth spurt that lasts until 2 years of age. If she is a preterm baby, it would be the ideal that her head circumference moderately exceed her growth percentiles for weight and length, indicating that her brain was experiencing "catch up growth" after the challenges her early life in the hospital.

There is no way at this very early period of life to predict well what the developmental outcomes will be for this little girl. If she was born prematurely, her mother received little or no prenatal care, the baby was drug or alcohol exposed, or suffered from asphyxia at birth or infections as a baby, there is a greater likelihood that the small head circumference means that the baby is at greater risk for mental retardation or other developmental delays. It would be helpful to request a more thorough history of the mother's health and prenatal course and the baby's birth, including Apgar scores. Apgar scores provide a picture of how vigorous and well the baby was at the time of her delivery. The higher the score, with 10 being perfect, the better.

All US children qualify for early intervention services to help babies grow and learn their best right from the start. These services are often provided at no cost. Here in Ohio, they are available through the Help Me Grow program. Parents may ask for an evaluation themselves or by working through their pediatrician to contact the Help Me Grow program, www.ohiohelpmegrow.org

This is such an important decision. If you obtain further information, please don't hesitate to contact Netwellness again for assistance in understanding the significance of the information. You may also wish to discuss it with the pediatrician you were planning to use as the baby's primary care professional. The best of luck to you.

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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