Growth in Children

Watching your children grow is exciting. Sometimes you may not realize how much they have grown when you see them every day. Your child’s health care team uses growth charts to keep track of growth over time. Read on to learn about:

  • Body mass index (BMI), including overweight and underweight growth
  • How to interpret the growth chart

and growth charts for children with special health care needs

Body Mass Index (BMI)

The BMI is a screening tool. It uses a person’s weight and height measurements to see if that person’s weight is normal, low, or too high when compared to his or her height.

This is how children’s weight is assessed:

  • At risk for overweight is any BMI above the 85th percentile.
  • Overweight is any BMI above the 95th percentile.
  • Underweight is any BMI below the 5th percentile.

The BMI has gained more attention in the last 10 years because more and more of our nation’s children are becoming overweight. Many parents feel that their child has a high BMI because he or she is simply “big boned” or has “baby fat” that will eventually go away. Unfortunately, research is showing that children who are overweight are at very high risk of becoming obese adults. Overweight children and adolescents are also at increased risk for chronic diseases such as diabetes, heart disease, and sleep apnea.

Based on the BMI, your child’s doctor may tell you that your child is at risk for becoming, or is already, overweight. Or, you or your child’s health professional may be concerned about your child being underweight. The BMI can spot either problem.

The Growth Chart

Growth charts can help track a child’s height, weight, head circumference, and body mass index (BMI) over time. Health professionals can use the growth chart to keep track of your child’s growth and as a gauge of overall health. Don’t use a growth chart as the only measure of health. It should be used along with other clinical information about your child.

There are separate growth charts for boys and girls because they grow at different rates. The growth charts are divided into two age groups: Infants (birth to 36 months) and children and adolescents (two to 20 years old).

For the infant group, there are four different measurement charts:

  1. Weight for age
  2. Length for age
  3. Weight for length
  4. Head circumference for age

For the children and adolescent group there are three different measurement charts:

  1. Weight for age
  2. Height for age
  3. Body mass index (BMI)

Each measurement chart is divided into 5th, 10th, 25th, 50th, 75th, 90th, and 95th curved percentile lines. The percentile curves are based on measurement data collected over the last 40 years about U.S. infants, children, and adolescents. The percentiles allow you to compare the growth of your child to others the same age and gender. For example, if your child’s height is at the fifth percentile, that means that five percent of children are shorter and 95 percent of children are taller than him.

Remember that there is a wide range of healthy shapes and sizes. A child whose height is at the 10th percentile can be just as healthy as a child whose height is at the 90th percentile. Your child’s health professional is not only looking at the percentile, but also at the rate of growth and change over time. If your child’s growth is moving from a higher percentile to a lower percentile quickly over time, or if growth is increasing quickly, this could be a cause for concern.

As you know, it can be hard to accurately measure children’s height and weight because they are wiggly. Or children may have conditions that make it difficult for them to stand or use a scale. But it is important to make sure that the height and weight measurements are correct in order to get an accurate BMI.

Resources MedCalc: Interactive Growth Charts 2000 Website of the Center for Disease Control and Prevention with National Center for Health Statistics Clinical Growth Charts

Website of the U.S. Department of Health and Human Services, Maternal and Child Health Bureau including the CDC Growth Training Module: The CDC Growth Charts for Children with Special Health Care Needs