Dear Attachment Parent: Help! I’m not sure my baby’s growth is on track. What should I do?
Note: We are Pocketful of Pebbles are not medical doctors, so we always advise getting a professional opinion if you are concerned about your child’s health. Unfortunately, not all pediatricians are up to date with accurate information, especially when breastfeeding is involved. Our goal is to arm you with information you can take to your doctor or other health care professional to advocate for yourself and your child.
When used properly, growth charts can be very helpful for determining how well your baby is growing and identifying potential problems. As most people have heard, there are two different sets of growth charts, the Centers for Disease Control and Prevention (CDC) charts and the World Health Organization (WHO) charts. The most important thing to know is that babies and children under 2 years of age should always be measured on the WHO charts. Unfortunately, not every pediatric practice is up to date on best practices, and some continue to use the outdated CDC charts. If you have any questions about your child’s growth, be sure that the growth patterns you are looking at are charted on a WHO chart.
Why is it so important to use the WHO growth chart?
The CDC growth charts were collected using a sample size of 4,697 babies and toddlers under two years of age in the United States. Only half of them had ever been breastfed, and only one third were still breastfeeding at three months old. This means that the CDC growth chart describes the actual growth patterns of about 5,000 American babies, who were mostly formula fed. As a result, the measurements do represent ideal growth patterns for babies. Don’t compare your own baby to them.
The WHO growth charts, on the other hand, are based on healthy, breastfed infants and intended to measure how babies should grow. They charts are based on 18,973 observations of 882 children from six different countries including the United States. These children had their growth plotted weekly as newborns, monthly as babies, and then every month until they reached two years of age. Unlike with the CDC sample, children were excluded from the WHO sample if they had risk factors that could potentially interfere with growth, such as having a mother who smoked during pregnancy, being born before 37 weeks or after 42 weeks, being part of multiple birth, having started solid foods at younger than 4 months old, and other factors. Perhaps most importantly, all babies in the WHO sample were breastfed. To be included in the sample, babies had to be predominantly breastfeeding at 4 months old AND still breastfeeding at 12 months old. Breastfeeding is the recommended standard for infant feeding, so these measurements represent the ideal growth patterns for babies. Even the CDC now recommends that only the WHO growth charts be used to assess the growth of babies and children up to 2 years of age.
The WHO growth curves versus the CDC growth curves
In the graphs below, the solid lines represent the CDC curves and the dotted lines represent the WHO curves. If you look closely, you can see that the solid (CDC) lines are below the dotted (WHO) lines on each chart until about 8 months for girls and 6 months for boys, after which the reverse is true. Remember, the CDC chart measures primarily formula-fed babies and the WHO chart measures breastfed babies. This matches up with the fact that breastfed babies tend to grow faster initially, but then slow their growth in later babyhood compared to formula-fed babies.
Growth curves for girls (left) and boys (right) ages 0-24 months old
I’ve plotted my baby’s growth on the WHO curve. Now what?
Now that you have your charts handy, take a moment to find each of your child’s measurements: weight, length, and head circumference. In addition to their current measurements, track down the previous ones.
The growth curves are plotted according to major percentile lines (5th, 10th, 25th, 50th, 75th, and 90th percentiles). Some parents worry when their baby measures in the 10th percentile, meaning that their baby’s growth is tracking the same as the 10% of babies in the WHO sample who were the smallest. Remember, if you line up the entire healthy population from smallest to biggest, someone will by necessity be smallest. Being small does not mean there is a problem. (Likewise, having a baby who is larger than 90% of other babies does not mean there is a problem either. This was my first baby, who is now a slim nearly 6 year old.)
It is also not uncommon for babies and young children to jump between percentiles in either direction (up or down), but when a child drops two or more major percentiles (e.g., from the 75th to the 25th percentile), it can potentially signal a problem. In these cases, it’s worth looking at each of your baby’s growth measurements: weight, length, and head circumference.
If your baby’s measurements have dropped less than two percentiles, there is usually no cause for concern. Babies and toddlers all grow at their own pace, with growth spurts and plateaus happening at different times in their development.
If your baby’s weight has dropped more than two percentiles, but height and head circumference are stable: This is usually classified as a “nutritional” problem. It could simply mean that your baby was unusually active since the last weight check and/or didn’t take in quite as many calories as expected. Did your baby recently start crawling or walking? That could explain it all.
If your baby’s height or head circumference have dropped more than two percentiles, but weight is stable: Keep in mind that moving around on growth percentiles is not uncommon, but talk to your child’s doctor to make sure he/she is not concerned about hormonal or genetic issues.
Should I cut back on breastfeeding?
Medical professionals who are uninformed about breastfeeding will sometimes suggest cutting back on nursing sessions in the hopes of improving growth. If you receive this advice, we recommend getting a second opinion. Breastmilk has more calories per ounce than just about any other food people regularly feed infants or toddlers, and greater fat content to boot. For example, breastmilk has 30% more calories per ounce (22 kcals/ounce) than whole milk yogurt (17 kcals/ounce). If you want your baby to grow, don’t cut back on the highest-calorie, highest-fat food. Instead, consider offering to nurse more frequently.
Again, talk it over with your pediatrician to be sure you are on the right track for your baby.
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