WHO versus CDC growth charts: WHO cares?

Ah, infant growth charts. Aside from those on your junior year SAT math section, no graph can inspire more fear and concern. FC’s percentile chart looks like a death-defying roller coaster – from the 10th to the 75th to the 25th. Fearlette’s is always at a consistent 20th, but considering her height was in the 75th, her weight to length line is disturbingly close to the bottom of the page.

I hate those growth charts.
According to yesterday’s Wall Street Journal, so do many other parents. Columnist Melinda Beck reports that: 
Parents often worry that their children are too tall, too short, too fat or too thin. These days, however, more kids are measuring “off the charts”—either above or below the standard ranges for height and weight that pediatricians use.

The wide variations are due in part to rising obesity rates, an increase in premature infants who survive, and a population that is growing more diverse. Yet the official growth charts from the Centers for Disease Control and Prevention still reflect the size distribution of U.S. children in the 1960s, ’70s and ’80s. The CDC says it doesn’t plan to adjust its charts because it doesn’t want the ever-more-obese population to become the new norm.

Beck goes on to explain how many are lobbying for the American Academy of Pediatrics to adopt WHO growth charts, as our current ones don’t reflect the growth patterns of breastfed babies. The movement has been going on for awhile, and I think it’s important to understand how the two types of growth charts differ.

The WHO growth charts are meant to act as a normative standard, as they were based on children who fulfilled specific criteria – “proper” nutrition (breastfeeding exclusively with complementary solids starting between 4-6 months), born at a healthy gestational age and weight, living with sufficient socioeconomic conditions, decent healthcare and breastfeeding support, etc. The charts are based on records of children fulfilling this criteria in Brazil, Ghana, India, Norway, Oman, and California between the years of 1997-2003.

The CDC growth charts are simply a snapshot of one general population (the midwestern United States) over 30 years. No babies were excluded based on any criteria. You can think about it like this: the WHO charts are based on an ideal; the CDC charts are based on a time-and-location-specific reality.

I am not a fan of the CDC charts. Just as they do not accurately address the growth trends of breastfed babies,  one could easily say that the current growth charts also fail to reflect the social, ethnic, environmental, and hell, I’ll say it – evolutionary – factors which are contributing to larger babies.

The problem is, neither do the WHO charts – in fact, I fear they will only make things worse.

There seem to be two separate concerns being expressed within this particular debate: one, that breastfeeding moms are being mistakenly informed that their babies aren’t growing sufficiently on breastmilk alone; two, that our nation’s babies are a lot bigger than they used to be, and the growth charts don’t reflect this. These two problems have incompatible solutions. Adopting a chart which skews lighter, as the WHO charts do, might help the breastfed kids seem more “normal”, but it would also make the majority of babies in this country seem disproportionately bigger. If it were an indisputable fact that larger babies were inherently unhealthy, one could argue that categorizing more babies as outside the “ideal” would be a good thing. As far as I know that isn’t the case. There is some correlation between faster weight gain in infancy and later obesity, but this is still a rather tenuous correlation considering the quality of the studies which suggest it. By adopting the WHO charts, I fear we will suddenly see an “epidemic” of “obese babies”; next thing you know we will be putting 4-month-olds on diets.  I know it sounds CoCo Puff Crazy, but check out what the authors of this report from the CDC comparing the two types of growth charts said about the subject:

Clinicians should recognize that the WHO charts are intended to reflect optimal growth of infants and children. Although many children in the United States have not experienced the optimal environmental, behavioral, or health conditions specified in the WHO study, the charts are intended for use with all children aged <24 months. Therefore, their growth might not always follow the patterns shown in the WHO curves. For example, formula-fed infants tend to gain weight more rapidly after approximately age 3 months and therefore cross upward in percentiles, perhaps becoming classified as overweight. Although no evidence-based guidelines for treating overweight in infancy exist, early recognition of a tendency toward obesity might appropriately trigger interventions to slow the rate of weight gain.

I’m not convinced breastfed babies would be immune to the Obese Baby label, either. The WHO growth standards on not based on American children; there are genetic, ethnic, and situational factors that play into growth, weight, and length of babies. We tend to be a rather, er, well-fed bunch; maternal diet can affect the amount of fat and other nutritional content of breastmilk, and the lifestyle of the mother can dictate how much milk a baby receives. An exclusively breastfeeding mom who works full time will likely have a baby who is bottle-fed breastmilk as much or more than s/he feeds at the breast;  studies have shown that it may be more the mechanism of feeding than the type of milk which influences weight gain.

Nor would universal adoption of the WHO charts necessarily negate a physician’s desire for intervention when weight gain plummets downwards. One of the women interviewed for the WSJ piece was a woman whose “5-month-old son, Elias, has slipped from the 50th to the 25th percentile.” Her answer to the guilt inflicted on her by her pediatrician was to consider “taking a leave from her job as an associate professor of human development at California State University, Long Beach, so she’ll be available to nurse on demand.”

A drop from the 50th to the 25th percentile at 5 months might not be seen as a cause for concern if pediatricians were trained in the growth patterns of WHO chart-compliant babies. But I think this quote underscores the problem with any type of growth chart: every situation is different. We don’t know enough about this woman’s story to know whether her doctor was an anti-breastfeeding alarmist, or merely a follower of the Hippocratic oath. (Please note: I am not making any sort of judgment on this mother’s situation, but I also think we need to look at these types of anecdotes critically, as they tend to get used as fodder for the ongoing infant feeding debate. I’m looking at the quote alone within context of the article, and trying to point out that there may be additional layers to the story, and that the solution may not be as simplistic as adopting new growth criteria.) Why would the mom feel the need to quit her job and “nurse more” as the solution? To me, this suggests that the mom feels her time away from the breast is the problem – it could be that the baby has a problem taking a bottle, or the mom has a problem expressing enough milk.I’d also question, since the drop in weight occurred around 5 months, whether adding solids might be a solution. There has been discussion in the medical community about relaxing the “six months exclusive breastfeeding” rule to “four months exclusive” at which point solids can be added to the diet, based on individual readiness and need. Perhaps this baby is one who is both ready and needy for a bit more sustenance. This has nothing to do with the adequacy of his mother’s milk or her employment status. Nor does it have anything to do with formula supplementation or which growth charts are being used. 
I understand the argument that the current charts are outdated in pretty much every way possible, and need to change. But I think a more helpful solution would to be to stop being slave to the percentiles, and instead use them – perhaps the CDC ones for formula fed babies, and the WHO one for breastfed babies – as merely a guide. If a baby is healthy, growing, and meeting developmental milestones, then who cares if she is in the 10th or the 80th? Especially if our only choices are to compare that a baby living in 2012 in Tuscon, Arizona to either some statistical hybrid of Gambian and Norwegian babies, or one from Wisconsin in the 1970s. Let’s not lose sight of the fact that the current system judges all babies (and parents) by unfair standards, and not allow this to be more kindling for the breast versus bottle pyre.

Suzanne Barston is a blogger and author of BOTTLED UP. Fearless Formula Feeder is a blog – and community – dedicated to infant feeding choice, and committed to providing non-judgmental support for all new parents. It exists to protect women from misleading or misrepresented “facts”; essentialist ideals about what mothers should think, feel, or do; government and health authorities who form policy statements based on ambivalent research; and the insidious beast known as Internetus Trolliamus, Mommy Blog Varietal.

Suzanne Barston – who has written posts on Fearless Formula Feeder.


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13 thoughts on “WHO versus CDC growth charts: WHO cares?

  1. My breastfed babies grew exactly how the experts say breastfed infants grow. They were both small (and remain small to this day). We ended up switching pediatricians for one of the reasons you cited above: she insisted my children were not getting adequate nutrition from breastmilk alone, even though they were gaining weight and height each month. My son was briefly labeled failure to thrive. She wanted to send my son to a pediatric gastroenterologist. When my daughter was a very tiny 16 1/2 pounds at one, she wanted me to feed her what is basically junk food to get her to gain weight. She was way too attached to her growth charts and instead if using them as a tool, they were a weapon and they obscured the simple fact that my kids are not genetically inclined to be large. My husband is a slightly built man who wears a size 8 shoe. I'm tall for a woman but have never been large. I finally got fed up and switched practices. A friend sees the original doctor and her boys are big. The doctor hassles her for their size, but seems to have missed the fact that their father is 6 foot 5!

    My kids are 5 1/2 and almost 8 and still smaller than most of their classmates. My son is 50 inches tall (at least, i have not measured him recently and I think he grew) and 44 pounds (which is a recent number) and very thin. But he's also active, healthy and doing great in school. Our current pediatrician is not concerned about his weight.

    As a new mom, being told that my child was failing to thrive was like a knife in my gut. I don't think it matters which set of growth charts doctors use, but rather the method in which they use them. Weight and height are only two values in determining the health of an individual.

  2. My formula fed baby has gone from the 10th down to the 5th and now the less than 3rd percentile for weight, just under 20lbs at 18 months. My pedi was concerned for a bit, but now just accepts that that is just how she is built since she is healthy and tall.

  3. I loathe those charts! and they are most certainly not an accurate depiction of infant health (I liken them as the same B.S. as BMI charting for adults).

    I completely agree about the statement you made about the diversity in our culture (I'm from Canada, which is similar in cultural diversity to the U.S.); my own background consists of three or four different european cultures, and then factor in my husband's background as well, and there's quite the mod-podge of genetics affecting our childrens' height/weight. On that note, I am a short, obese woman who suffers from gestational diabetes. Although there is absolutely no evidence that shows incidence of large-for-gestational-age infants in cases of well-controlled diabetes (gestational or otherwise), my youngest daughter came out a gigantuan baby. Her weight, 9lbs3oz, put her in the 97th percentile- HOWEVER, her length, at 23 inches, put her right off the charts! A lot of doctors (and in fact, ALL of the nurses on the ward I delivered at) would blame me, my diet, and lack of apparent “health” on my daughter's large size- I was very fortunate to have an amazing pediatrician who was able to look past the charts (and me and my size) and reason that her size had nothing to do with being unhealthy/obese/overweight or her method of feeding; and everything to do with the Nordic genetics handed down from my paternal grandmother, a healthy, active 90 year old woman who stands at just over 6 feet tall. He was able to point out to me that of COURSE she was going to weigh a lot- whether or not I had diabetes- because she was 23 freaking inches long!!

    That baby girl is now a happy, healthy 2 year old-who was exclusively formula fed; her height is still ridiculous- I almost expect that she'll be taller than me by the time she reaches kindergarten, but in no way, shape, or form is she overweight or obese. Summed up, the charts, if used as a loose guideline- and both height and weight need to be considered equally- as well as a general curve of growth for the specific child being followed, have the potential to be a useful tool to point out potential growth issues. Unfortunately, the charts are being used without any common sense and the whole point is being lost.

  4. I hate those charts. I'm sure they help with unhealthy babies a bit I guess…but otherwise they are horrible. My son was always “underweight” but incredibly active and tall for his age. The pediatrician knew that was his norm, WIC out here didn't though and was lecturing me on how he needed to gain weight. I tried explaining that was the norm for him and how it runs in the family, but she didn't care. She also labeled by daughter who is also very tall for her age (90th percentile apparently) as underweight. However she has rolls on her thighs and arms and chubby cheeks, how is that underweight? The lady must not be observant. My daughter is very healthy and alert for her age.

  5. Growth charts are designed for looking at growth trends, not size at one time. Babies have all different weight to height proportions that are normal. It is if weight falls or rises in relations to height, if growth percentiles are crossed, that there might be a problem, and even then it isn't necessarily so.

  6. I never like to extrapolate our individual experience with across the board trends. That being said, my formula fed guy was huge at birth (99th % for height, weight and off the charts head) and continued that for 9 months, when he stopped gaining weight but continued to shoot up, a trend that has continued for 4 years now! He's still off the charts tall (99th%), but his weight is on the lower end, something like 26%. His dad is tall (6'6') and skinny and my son is built exactly like him. I think that his BMI now is much more dependent on 1) his genetics and 2) what we feed him now (no simple sugars, no white carbs, no factory meat or milk (what can I say, we're just a bunch of hippies!) than what he ate as an infant.

  7. I had no idea that the WHO charts were meant to be normative – when people advocate for the WHO instead of CDC curve I've most often heard them say the WHO curve better reflected the reality of BFed infants' weight gain. Good to know. However I keep going back to the same puzzle of calories – if babies know when they are full or when they are hungry, and breastmilk has the same, or slightly more, calories compared with formula per ounce, why do we believe FFed babies are bigger? I guess the bottle-goes-faster argument could work, but I wonder about ethnic differences being used as proxies re: breast or bottle feeding. It might be good to compare BFed and FFed babies within a non-Western cohort rather than FFed in US Midwest vs. BFed in India.

  8. And PS on more realistic growth charts, once again I can't help but think what a wonderful resource pediatricians' records could be – couldn't they pool growth charts for babies they measure and develop, say, a state-level average growth chart, or use their records to check for health abnormalities that may have been indicated by aberrant growth patterns. But heaven forbid one should work according to changing realities and accept new data…

  9. I hate the charts as they have been our life for the last year and a half dealing with my daughter's weight and health issues. She sees specialists at Children's Hospital of Philadelphia where they have been using both charts. Two questions.
    1. are breastfed babies really smaller than average??? I have only seen huge roly poly chubber breastfed babies. And EVERYONE I know breastfeeds. Their babies always seem plump almost to the extreme. And at the same time I haven't seen the pump babyhood having any effect on their weight once they are older. Average weight children.
    2. Does it really matter what chart is used. I never worry where my children are on the chart. I know my kids are tiny. I worry that they are maintaining a growth curve. Make sure kids are growing and developing in a healthy way and then it makes no difference……does it?

  10. Our pediatrician seems to use the chart as a guideline. I am not even sure which chart he uses (WHO or CDC). Between genetics and prematurity, my sons were never destined to be large. In weight and height for age, they have consistently been in/around the 5th percentile. The key word is “consistently.” The doctor could see from that pattern that they are growing at a normal rate. They started from a smaller point, so unless their rate of growth speeds up somehow, they will never catch up to their peers, at least not before puberty. Also, despite their small size, their weight for height has always been around the 50th percentile, meaning they are an average weight for a child who is that tall, it's just that most children that tall are younger than they are.

    I am surprised this is even a big deal—tracking growth patterns is important to ensure healthiness, but worrying about exact percentiles, or that your plump baby is going to be an obese adult is silly. I don't think we have all the answers for obesity, but my impression from what I have read/heard recently, Americans' diet has significantly changed over the last 40yrs or so, and our portion sizes are way too big. Many Americans drink a lot of soda, and I doubt anyone will argue that soda has great nutritional value. Americans are more sedentary too.

    I think a lot of a person's size comes from genetics, and no matter how much kale she eats, or how many miles he jogs, they may not be able to be “ideal.” Still, I think it can only help if we offer appropriate nutrition with appropriate portion sizes to our children, and if we encourage them to be active. I think those factors will have a bigger effect on a person's weight/health than what they ate in their first year of life.

    Ultimately, if growth charts are going to be used, it may be helpful to rewrite a chart to reflect reality in America. I think it is more helpful to say that 50% of American baby boys weigh 22lbs at 1yr now, vs. saying that 40yrs ago 50% of baby boys weighed 18lbs at a year, and then deciding that most baby boys are fat. Or maybe we can stop comparing all the American children to each other, and simply follow individual children's growth patterns, as a tool to monitor health.

  11. Hey FFF! Quick fact update needed on this post, hope you're not offended that I'm mentioning it. Your WHO exclusive breastfeeding / solids introduction recommendation note about starting complementary foods between 4-6 months is incorrect. They've updated it. “Review of evidence has shown that, on a population basis, exclusive breastfeeding for 6 months is the optimal way of feeding infants. Thereafter infants should receive complementary foods with continued breastfeeding up to 2 years of age or beyond.” http://www.who.int/nutrition/topics/exclusive_breastfeeding/en/

    But other than that, great post. I also hated those pesky charts when my children didn't seem to line up right on the chart the ped printed for us with the baby's dots no where close to the line. My children don't even line up to each other on growth patterns so far so I don't even bother being upset about those charts anymore. Oh, and I just noticed your last sentence. Was someone being rude about the difference between the breast fed and the formula fed baby charts?

  12. So I think I can finally put my finger on what bothers me about the difference in the charts.

    The WHO charts are being called “ideal” infant growth because the babies are breastfed. BUT, what they are showing (in the literature I read) is that these babies are growing FASTER than their CDC-studied counterparts the first 4-6 months and slower the rest of the first year. Which is when solids are introduced. But somehow, the “idealness” is being chalked up to the breastfeeding and there's no discussion of the solid feeding – what they are eating, how much, how often.

    There are many who would say that “solids are just for practice” that first year, but that discounts the fact that everything a baby eats COUNTS. It all goes towards nutrition and caloric intake, it all affects a baby's growth.

    Maybe the WHO chart is still “ideal”, but I would really be curious to see the the difference in solids-eating (and how that affects their fluid intake) between breastfed and formula fed babies to see if the discrepancy in growth can be explained there. Solids-feeding gets so lost in the battle of breast vs bottle, even though it accounts for increasingly more of a baby's nutrition as the year goes on.

  13. Those charts have been a big part of my life for the last year. My daughter was born with a Congenital Heart Defect. When she was born she was in the 50 percentile for both height and weight. As time went on she fell further down the chart. When it looked like she was not gaining weight or height adequately, her cardiologist determined it was time for her heart to be repaired. At the time we discovered that she also had a congenital tracheal abnormality that had to be repaired. In general she was not getting enough oxygen. She was never given a failure to thrive label, although the hospital in Chicago kept insisting she had one. She had problems eating after her surgery. She has finally almost caught up. She's small in general and probably always will be, but she has put on an amazing amount of weight in the last 6 months. I'm not a fan of statistics, but I will say that in this case it let us know when it was time for the surgery that saved my baby's life. :)

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