Percentiles Explained: Understanding Your Child’s Growth Charts
Summer has ended and school is upon us with its supply shopping, uniform buying, open houses, practices, and for many children, a check-up with their pediatrician. One of the most important components of a well-child visit is assessing a child’s growth–primarily by plotting his or her measurements on a standard growth chart. Although those curved lines and percentiles may seem daunting, growth charts are not difficult to understand.
What are growth charts?
Growth charts were created using decades of data collected about children’s growth. In children less than two years old, growth charts developed by the World Health Organization are used to plot length, weight, and head circumference. Children 2-20 years old use the Centers for Disease Control and Prevention (CDC) growth charts on which height, weight, and body mass index (BMI) are recorded. Boys and girls are plotted on different curves because their growth patterns are different. These charts serve as a reference for pediatricians–a tool that allows comparisons.
What do the percentiles mean?
Growth charts allow pediatricians to compare your child with other children of the same age and gender. The charts consist of smooth curved lines that represent different percentiles. The higher the percentile, the bigger the child is compared to other children. For example, if your five-year-old son’s weight is at the 25th percentile, then 25 percent of five-year-old boys weigh less than him and 75 percent weigh more.
Healthy children do not have an ideal or a goal percentile because growth is influenced by genetics, environment, nutrition, activity, and illness. It’s helpful to look at a child’s growth at one moment in time, but it is more valuable to observe his or her growth over time by comparing the measurements from today’s checkup with previous ones. Your pediatrician looks at the overall growth trend to ensure that your child is growing normally.
When should I be concerned?
Remember that growth charts must be interpreted in the context of a child’s overall wellbeing. However, certain growth patterns may prompt further investigation or intervention from your pediatrician:
- A child’s growth that suddenly changes percentile curves. For example, a child who has consistently been on the 85th percentile curve for weight suddenly drops to the 25th percentile.
- Children greater than the 95th percentile or less than the 5th. Family members’ growth helps determine if this is a problem.
- Height and weight percentiles that are very different or changing at different rates. This may indicate a child is overweight or underweight.
Are all children represented by these growth charts?
Children provided with good nutrition, access to health care, and good social and general living conditions have similar growth patterns, regardless of race or ethnicity. There are specialized growth charts for premature infants and children with certain health conditions, such as Down syndrome and Turner syndrome. These charts have some limitations, but they are useful additions to the standard growth charts.
Growth is a reflection of a child’s overall health and nutrition. It’s one of the most important aspects of a well-child visit. Your pediatrician would love to show and discuss your child’s growth chart at his or her next check-up. You can also download these charts yourself or read more about growth charts on the CDC website. ■