Growth Charts for Kids

Growth charts are ubiquitous when it comes to doctors appointments for babies and toddlers. They’re what doctors use to assess, and talk with you about, your child’s growth. But just what exactly is a growth chart and what is it looking at?

How Growth Charts Were Created

Before we get too far into how growth charts are used today, let’s talk a bit about how growth charts were developed. Here in the US, there are two different growth charts used. One is from the Centers for Disease Control (CDC) and one is from the World Health Organization (WHO).

The CDC Growth Charts

The growth charts from the CDC were developed by looking at how children throughout the US grew at a certain time. Many of the babies in the data set were formula fed, although the data was revised in 2000 to provide a more balanced spread of formula and breastfed babies. (Ref)

The original data for babies 0-12 months in the CDC charts was taken from a small group of infants out of Ohio. They were primarily all white with a high socioeconomic status. In other words not exactly a representative sample! 

The updated version in 2000 included a more representative sample, but the data still had a good deal of holes in it. The CDC growth charts were also created to be references, meaning that they show how kids grew at a certain time. They are not standards, like the WHO charts, which can be used to evaluate how well-nourished children would be expected to grow.

The WHO Growth Charts

Unlike the CDC charts, the WHO charts were developed through a well-designed research study that was specifically created for the design of the growth charts. The WHO growth charts were created to be standards. As well as to help doctors and other healthcare professionals assess a child’s growth. (Ref)

They are much more representative of a wide variety of ethnicities. They also use breastfed children as the standard for growth patterns in the first two years of life. The CDC recommends using the WHO growth charts from ages 0-2, and then switching to the CDC growth charts up to 18 years. The WHO growth charts include children ages 0-5 years old.

How Growth Charts Should Be Used

Growth charts are intended to be used to help medical professionals assess how a child is growing. They are intended to be used to see a child’s own growth trajectory compared to a standard. Not as a diagnosis of a child’s health or well-being.

But just what does that mean?

As parents, it’s really tempting to go into a visit with your child’s doctor and be focused on how much your child weighs or how tall they are. To worry that if they are small and low on the growth scale that it means that something is wrong. Or if they are on the upper end of the growth curve that they are overweight and you did something wrong.

But that couldn’t be further from the truth!

Growth Charts Are A Trajectory Over Time

When we look at where a child falls on the growth curve, we are simply plotting their trajectory over time. From one point to the next, where are they on the chart? By the very nature of charts and percentiles, some kids are going to be at the bottom. Some kids will be in the middle. And some will be at the top. Because that’s how percentiles work! Someone has to be in the bottom. And someone has to be at the top. We can’t all be in the middle.

If your child happens to be in the bottom 5% of the growth curve, that doesn’t mean that they are underweight and need to gain weight. It means that they are in the bottom 5% of kids for their age. That’s it. They’re smaller than we would expect 95% of other kids to be.

It doesn’t mean they’re sick or that they aren’t thriving. It simply means they’re small. The same thing goes on the opposite side of the curve if you have a child at the top of the growth curve.

Using Your Child’s Growth Curve to Assess Health

Now let’s talk about your child’s specific curve. We’re going to leave out all the talk about where they are compared to everyone else on the curve. Let's simply talk about the actual curve you see when you plot out their growth.

As a health professional, that is really what I’m going to focus on. Is your child generally holding steady? If they were at 80% before, are they still around there? Or did they fall down to 25%?

And here’s the thing. If they did fall down to 25%, it still doesn’t mean there’s anything wrong! Same thing if they jumped on the curve. We use growth curves as one data point. It is simply a part of the assessment that needs to be done. Because a fall on the growth curve without anything else going on is unremarkable!

A fall in the growth curve that leads to a discussion with parents about any problems that might have occurred, on the other hand, is helpful. The growth curve and how your child is tracking can be used as a screening tool to help health professionals probe further and see if anything is happening. But it certainly isn’t intended to, or able to be used, as a single diagnostic tool.

Problem Solving Growth Chart Issues

If your doctor talked with you about your child’s growth chart previously, and they were concerned, use this article to help you evaluate that concern.

Unfortunately, there are still many health care professionals who use growth charts incorrectly. If you were told that your child needed to gain or lose weight because of where they fall on the growth chart, know that that is an incorrect use of the chart! Just because your child is, say 3%, it doesn’t mean that they need to gain weight, that you need to help them catch up, or anything along those lines.

It’s important to look at everything else that’s happening. Is your family small? Has your child always been on the small side? Was there a big drop, and have you noticed anything change that could coincide with that?

The Typical Expectation

Most kids will fluctuate percentiles at some point as they grow. Most kids will have a drop or rise. It is normal, and not a concern! Unless there is something else going on, a drop or rise doesn’t usually mean that you need to feed them more or less food. Especially after only a one-time drop that’s not associated with any problems occurring.

Let your child grow at the rate and pace that is right for them. They aren’t a number, they aren’t just a statistic. We can’t expect every child to grow exactly as predicted. And if you have a child who is at the bottom or the top of the chart, has fallen or risen percentiles, or anything else associated with the growth curve, know that it is not an indictment of you.

Where your child is on the growth chart doesn’t mean that you are feeding them too much or too little, that you’re doing it wrong, or anything else. It is simply one piece of information that we use to help figure out what is going on, not a diagnosis!