Infant Head Size

Susie McGee
doctor measuring an infant

Pediatricians use growth charts to monitor a variety of newborn measurements, including infant head size.

Importance of Growth Charts

Parents often ask their pediatricians about their child's percentile on a growth chart. This is more than just curiosity. Parents want to be reassured that everything is right with their infant, and these charts are a standard feature of doctor's visits.

Growth charts are used as a comparison to other children of the same age and to document a pattern of growth for an individual child. Growth charts are often referred to when there are other indications of a possible health problem.

Use of Growth Charts

Doctors input several measurements when using a growth chart, including length, weight, and head circumference. While these numbers certainly contribute to the determination of a child's overall health and development, there are other factors that must be considered. As a doctor examines a child and monitors his or her growth, he also considers that child's genetics, environment, nutrition, physical activity, and any health issues which can influence a child's measurements.

If a child's measurements fall into the upper or lower percentile or exhibit a disruption in his developmental pattern, does this necessarily mean there is a problem? Not at all. In many cases, a child may be perfectly healthy, and genetics or environment may have simply come into play. For example, a small infant head size may be directly related to parents who also have smaller sized heads. In other instances, a preterm birth may be the reason for a smaller head circumference.

It's also important to remember that not all children are measured on the same growth chart. For example, girls and boys grow at different rates and patterns, so separate charts must be used. In addition, charts can differ according to a child's age as well.

Measuring Infant Head Size

An infant head size measurement can give physicians an idea about a baby's brain development. When a baby's head is considered bigger or smaller than other babies' head sizes in the same age range, a problem may be indicated. Health issues could include the following:

  • Larger than normal head size-This may be the result of hydrocephalus, which is excess fluid in the brain.
  • Smaller than normal head size-This may be an indication of a lack of normal brain development.

Recently however, studies have begun to indicate a correlation between babies' head size and development within the first year and an increased risk of autism. According to the article entitled "Infant's Head Size Offers Clues to Risk of Autism and Diagnosis" published in the Seattle Post, a small head measurement at birth that is "followed by a sudden and excessive increase in head size in the first year of life, appear to be early warning signs that an infant is at risk of being autistic." While autism is not usually diagnosed until a child is closer to the age of two and beyond, this accelerated brain development is thought to predict the seriousness of the condition as the child grows.


Physicians often refer to growth percentiles, as they plot a child's development. This data is typically shown as a curved pattern of lines on a chart. The higher or lower the percentile that is plotted, the bigger or smaller the measurement is respectively for a child compared with other children who are the same age and gender.

More Information

The website Infant Head Circumference Chart offers an online calculator that shows how your child's head circumference compares to other babies. If your child's head size receives a percentile value of 60, this indicates that your baby's head circumference is greater than 60 out of 100 babies. Keep in mind that the use of this calculator is for curiosity only, however. While you can certainly keep up with your child's measurements, you should pay more attention to the developmental milestones he achieves. As always, if you have any worries or concerns, contact your pediatrician immediately.

Infant Head Size