What’s YOUR Curve? How to interpret your child’s growth percentile
Weight curves. Percentiles. Ask the average parent about their child’s growth percentiles and they’ll likely laugh and think you’re joking. Other than enjoying the information given at a well-child visit, many parents go through their children’s lives without any real thought to what percentile their child is in. Or why it matters. And some won’t even know what you’re talking about if you asked.
But parents of tube-fed kiddos? Percentiles (and your medical team’s opinion on where your little one should be) is basic small talk. It’s a part of every day and every decision.
When we start working with families who are looking to wean their little ones, one of the most common concerns is voiced by saying, “But my kiddo doesn’t have any weight to lose! He’s only in the 1st percentile!” Often, these parents have been told by their medical team that their little one must be at “x” percentile before they can even consider a wean.
Well, I’m here to tell you, there’s no current research, anywhere, that shows that a particular percentile is the “healthiest” or “ideal” for most children. With the exception of rare medical diagnoses, the 50th percentile, for example, is not magically healthier than the 10th. Or even the 1st. In fact, no percentile would exist if many kids didn’t healthily fall into it. And even the “definition” of Failure to Thrive (FTT) is often inconsistently applied because percentiles are interpreted in a variety of ways.
Yes, we all want to see kids growing and thriving. Yes, we know that relatively consistent growth is necessary to support development, neurological flourishing, and your child’s full potential. But, we don’t really know what that “growth” looks like for any one, individual kid. Just like adults vary in sizes, so do kids! And as a momma to a kiddo in the 5th percentile (or below!), I can confidently tell you that hasn’t made her one bit less smart, active, developmentally appropriate, or healthy than her older brother who is in the 70th+ percentile.
So what DO I look for to assess if a kid is healthy and growing successfully? Lots of things!
Parents’ and siblings’ height and weight: do they even HAVE the genetic potential to be 6 feet tall?
Growth history: has your child maintained her OWN weight curve? Length curve? Even if their curve is at the “bottom” of the percentile charts (or off them!), if the child is following her OWN curve well, that’s typically a good indicator of adequate nutrition and health.
Appropriate chart: if your child was premature, intrauterine growth restricted (IUGR), small for gestation age (SGA), has a genetic condition that affects growth (Down Syndrome, for example), his growth is expected to follow a different trajectory than his full-term, 8-lbs at birth, no genetic complication peers.
Accurate measurements: for length, this means TWO different practitioners taking the measure, separately, at the same appointment, and if those numbers don’t agree, getting a third! In babies, especially, a ¼ inch can be the difference between the 5th and the 25th percentile! And for weight, be sure your baby is weighed naked every time, and hopefully, always before or always after eating!
Age/development: we EXPECT kids to plateau as they become more active. We EXPECT growth to often “leap frog” in the toddler years, with length jumping up on month or two, followed by weight, taking turns back and forth. We EXPECT to see shifts as kids start eating more by mouth, transition from breastmilk to solids, get sick and recover, etc.
Your child’s tolerance of the current feeding volume: a child who is vomiting frequently is less likely to gain as sufficiently as a child who isn’t.
BMI/Length-to-Weight ratio: in this respect, we like to see proportional kiddos over super chunky, but super short kiddos!
Length growth: kids don’t go up in length if they’re not getting adequate nutrition! Weight is a short-term indicator of nutrition status, while length is a long-term one. In other words, if your kid is getting longer, they’re very likely getting enough food!
More to the point? Your child isn’t and shouldn’t be just one number! There’s so much more to consider in order to determine if your child is thriving or needing some additional support! This is why a particular weight percentile should never be the sole determining factor for whether you child is ready to safely begin a weaning protocol.
The truth, though, is that it’s difficult not to fixate on the numbers we see – not to feel like the 90th percentile is somehow better than the 3rd. But the truth is, there’s no real evidence that actually suggests that! Often, the desire to get a child to a “goal” percentile is based more on the comfort of the practitioner and less on any actual evidence. So the next time you feel the pressure to push calories towards a certain percentile, ask yourself why? And don’t be afraid to ask your team, specifically wondering, “What evidence suggests that this percentile will be “healthier” for my child?” And if there is no true answer to that question, try to rest in the knowledge that if your child is following his or her established growth curve – at whatever percentile – he or she is likely doing wonderfully! And so are you!
Aubrey Phelps, MS RDN PPCES IFNCP
Baker, J. Ideas for transitioning off of a feeding tube
Jaffe A. Failure to Thrive: Current Clinical Concepts. Ped Rev. 2011 Mar; 32(3):100-108