Whether or not you’ve had children of your own, you’re probably still familiar with the practice of charting a child’s height.
Changes in height can be marked on a doorframe, the inside of a cabinet, or on a fancy height chart, but no matter how it’s tracked, it’s always fun to see how quickly a kiddo is growing. Keeping track of a child’s height as he or she ages is also important from a medical standpoint. At each appointment, a doctor (or nurse, more likely) will measure a child’s height as well as their weight. The new measurements will be compared with older measurements from the same child as well as with national averages of each measure to determine growth percentiles.
Growth percentiles are simply a way to compare a child’s measurements against other children in the United States of the same age and gender (boys and girls grow at different rates). Doctors use these numbers to make sure that a child is growing appropriately based on the national average. The higher the percentile number, the bigger the child is compared with the national average. Conversely, a lower number means the child is smaller. For example, a child in the 74th percentile for weight weighs more than 74% of children their age, while a child at the 23rd percentile for height is shorter than 77% of similarly-aged children. No matter how big or small, growth percentiles between the 5th and 95th are considered normal.
Growth charts have been used since 1977, and the charts used today were developed by the World Health Organization (WHO) and the US Centers for Disease Control and Prevention (CDC). Children under 2 years of age are compared with the WHO’s chart; older children’s growth percentiles are based on the CDC’s measures. Furthermore, head circumference is measured until children are 3 years old to give information about brain development. After that, weight and height is used to calculate body mass index (BMI) as an additional measure of growth.
However, what is more important than the growth percentile is how the child is growing in relation to their own personal growth curve. Sudden, significant deviations from the child’s curve may indicate under- or overfeeding, illness, or a development issue. It’s important for these measures to be taken consistently so that any concerning changes can be addressed quickly. Babies grow at their own pace; they may go from a low percentile to a much higher percentile after having a growth spurt, but as long as they are largely following a consistent growth curve that’s unique to them, there isn’t cause for concern.
A child’s height and weight is dependent on a variety of factors, including genetics, diet, activity level, and environment. Just like adults, children come in all shapes and sizes, so although it’s helpful to compare a child’s growth to the national averages, the growth charts are certainly not meant to be a one-size-fits-all solution. As long as a child is growing at a rate that’s suitable for them and is otherwise happy and healthy, they’re good to go!
Did you keep track of your height growing up? Let me know in the comments below, and be sure to subscribe for more science on babies!