Off the Chart Growth: Reading and Understanding the Importance of Pediatric Growth Charts

Article provided by Rebecca Berman, FNP, RefuahHealth Pediatrics

My sister used to dread taking her firstborn, Yudi, to his well visits. Everything would go fine until the baby was weighed.

“The pediatrician would show me the growth chart, and there Yudi was below the bottom line. Again,” she said, feeling guilty and inadequate.

So, she did everything she could to plump Yudi up – fed him avocado and increased feeding frequency. But those growth charts made her miserable!

Growth charts are a regular part of pediatric well visits. They measure weight, height and head circumference and demonstrate how a child compares with other children their age. Parents, like my sister, frequently wonder what a child’s percentile means and its importance.

Official tracking of height and weight began in 1977 when the US National Health Center for Statistics published the first height and weight charts based on data from thousands of kids, mostly living in the Midwest. These charts have been revised to reflect updated data, with the most recent one published in 2000. There are supplemental charts for children with very high BMI, very low birth weight and conditions such as Down syndrome. 

The point of the US charts is to show average heights and weights; not to judge kids as successes or failures. When a parent hears that a child is in the 25% percentile for weight, it simply means that if you lined up 100 kids by weight the child would be heavier than 24 of them and lighter than 74 of them.

The real goal of your child’s chart is not to rank children against their peers, but to track how they are developing based on his or her past growth. 

As pediatricians, we look at the chart and check that the child is staying on his or her usual growth curve. Just as adults vary in height and weight, so do children. Children who are staying on their regular percentile line for height and weight are developing in a way that is right for them.

Usually, by age two, children settle into their own percentile curve. However, the most intense interest in weight percentiles happens before then, in the first year of life. This is because regular weight gain is a signal of overall health in an infant. If something is not right, we will see it in the weight well before the height is affected. 

When my sister brought Yudi in for his four-month well visit, the pediatrician noted that Yudi had dropped from the 25th percentile to the 5th percentile. A plunge down two percentile lines meant that Yudi was at risk for “failure to thrive.” When a child falls below their weight curve, a pediatrician wonders why this child isn’t gaining weight. Is it underfeeding? Is there an issue with his thyroid? Is he anemic? Yudi’s pediatrician made recommendations related to feeding and asked my sister to return in a week for a weight check.

Parents also become concerned with growth charts when their child’s height appears in the lower percentiles. Again, if a child’s height is following their individual growth curve, they are right on track!

If the growth curve does not climb as expected, but flattens out or drops significantly, a child may be experiencing a growth delay. In most cases the child will hit a nice growth spurt soon. In the meantime, parents can reach out to their provider to discuss possible issues. Basic blood work can confirm that your child’s body is functioning properly. If your provider is concerned, he or she may recommend that you see a pediatric endocrinologist.

Today, Yudi is a tall 10th grader who does well in school. He never got past the 10th percentile for weight, but now his mom knows that this is just how he is, growing and thriving on his very own curve.