The growth charts provided by the CDC and the WHO have been the source of many the mommy competition, doctor concern, and confusion all around. Moms brag that their baby is in the 90th percentile in height, or they'll express worry because percentiles are low. Doctors will often suggest a child is supplemented or introduced to a very fatty diet because they're below the 25th percentile.
Most people, including those doctors, don't even seem to understand how the growth chart works, and when the number should be a concern. And, moms, there's really nothing to brag about at all.
The CDC growth charts that are commonly used are based off of formula-fed babies, which is why all doctors have finally been told to switch to the WHO's growth charts, which are based off of breastfed babies. The biological way to feed babies should be the baseline.
Breastfed babies often fatten up quickly and then the weight tapers off, but formula fed babies gain at a steady rate, so around the point weight tapers off in breastfed babies, it's common that doctors point to a CDC growth chart and declare that since the baby's weight was dropping percentiles, they needed to be supplemented. We now know that that's untrue, and many the breastfed baby was supplemented merely because the doctor didn't understand normal growth of a breastfed baby. (Rule of thumb: Don't get caught up in numbers!)
At birth, if you received IV fluids and drugs, your baby's weight can be high since they're plumped full of saline, too. To get a baseline weight for your infant, you need to wait until they've dropped to their lowest weight before they start regaining. That low point is their birth weight, and natural percentile. Any weight gain after birth should be judged from that point, not the saline-plumped high weight.
Know that all children are different, and there are going to be very tall and very small children. Having a child in a very high percentile honestly gives you no bragging rights -- that just means your child is tall. Mine's short -- so what? There has to be average kids, short kids and big kids, lean kids and thicker kids. There is no right answer or mommy competition in chart stats.
A child at the 3-5th percentile (CDC chart) or 10th percentile (WHO chart) isn't automatically unhealthy, just as a child who is in the 99th percentile in weight isn't automatically fat -- it merely means that for their age and gender, they weigh significantly less or more than the average child their age. Often, their height will be within 20 digits or so of their weight, so the light weight is usually shorter, and the heavy weight is usually tall. Neither is an automatic health concern all on it's own.
Height and weight do not need to match either -- as long as your child is healthy and growing at a good rate, their numbers are just as unique to them as their fingerprints. Sometimes percentiles will fluctuate without need for concern. A baby who was incredibly chunky will often start thinning out as they become active, and even drop numbers or even pounds -- as long as there is no other noticeable concern with weight loss, this is acceptable.
The CDC also specifically stated that the growth charts are intended to be used as a reference, not a diagnosis. Children with optimal diets with no medical problems will not necessarily stick to these charts. A deviation from percentiles should be a cause of further investigation, NOT a reason to start changing the baby's diet immediately.
Too many of my friends have reported their doctor wanting them to start loading up their child's diet with oils, fat, and even unhealthy things like ice cream and sugar, merely to put on weight. I won't get into how weight gain should be done with healthy foods, but the point here is that their doctors told them to do it for one reason -- their child was thin. They didn't drop weight, they weren't unhealthy. They were just thin. Since when is naturally thin a bad thing? In both cases, and even in the case of my son, the thin boys took after their fathers, who are very thin and were thin children as well. Family history can easily point to growth trends, if you take a moment to look at it.
All these charts mean is that your child is heavy/light/tall/short compared to other babies their gender and age -- that's it. When in doubt, watch the CHILD, not the chart.
Do you understand how to read the growth charts?
Image via tomhe/Flickr