WHO vs. CDC Growth Charts: Which Does Your Pediatrician Use?
WHO and CDC growth charts look similar but measure different things. Learn the key differences, which chart applies to your baby, and why it matters at the 6-month visit.
Srivishnu RamakrishnanApril 9, 20268 min readIf you've ever compared your baby's growth printout from an app with the chart on your pediatrician's wall, you might have noticed the numbers don't quite match. That's probably because you're looking at two different reference standards — the WHO and CDC growth charts — and they're not the same thing.
Understanding the difference affects how you interpret your baby's percentile, especially in the first two years.
Two Standards, Two Different Questions
The WHO Child Growth Standards and CDC Growth Charts were built for fundamentally different purposes:
| Feature | WHO (2006) | CDC (2000) |
|---|---|---|
| Core question | How should children grow? | How do US children actually grow? |
| Study design | Prescriptive (optimal conditions) | Descriptive (cross-sectional survey) |
| Data source | 6 countries, 8,440 children raised under ideal conditions | US NHANES surveys, 1963–1994 |
| Feeding standard | Exclusively breastfed ≥ 4 months | Mixed (formula and breastfed) |
| AAP-recommended for | Birth to age 2 | Age 2 and older |
| Best for | Infants and toddlers globally | School-age US children |
Source: AAP Clinical Report, 2010; WHO Multicentre Growth Reference Study Group
The WHO chart asks: given optimal nutrition and healthcare, how should a healthy child grow? It was built by recruiting breastfed children whose mothers didn't smoke, had access to good healthcare, and lived in non-altitude environments — across six countries on four continents.
The CDC chart asks: how do American children grow? It's based on survey data from the US population, which includes children on formula, children in various socioeconomic conditions, and data collected across several decades when formula was more prevalent.
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The Breastfed Baby Problem
This distinction has a real practical implication. Breastfed babies naturally grow faster than formula-fed babies in the first 3–4 months, then slower from about 6 months through 12 months. The WHO chart captures this natural breastfed growth curve because its reference population was breastfed.
The CDC chart's reference population was partly formula-fed, so it shows a generally faster weight gain trajectory in the 6–12 month window. The result:
- A breastfed baby who is gaining weight perfectly normally may appear to be gaining slowly on the CDC chart
- On the WHO chart, the same baby's weight gain looks exactly right
This is why the AAP updated its guidance in 2010 to recommend WHO charts for the 0–2 age range. A baby dropping from the 50th to the 20th percentile on the CDC chart might just be a normally growing breastfed baby — and using the WHO chart would show they're right on track. If you want to check your baby's measurements against both standards, see our pediatric growth chart online overview.
How to Read Each Chart
Both charts work the same way visually — a series of curved lines represent percentile thresholds (typically the 3rd, 10th, 25th, 50th, 75th, 90th, 97th). Your child's measurement is plotted and compared to these curves.
The interpretation principle is the same regardless of which chart:
- Consistent tracking along any percentile curve = healthy growth
- Crossing downward across two or more major percentile lines = warrants investigation
- Crossing upward = usually fine, but monitor
| Child's Age | Recommended Chart | Measurements Included |
|---|---|---|
| Birth to 24 months | WHO Child Growth Standards | Weight-for-age, Length-for-age, Head circumference, Weight-for-length |
| 2 to 20 years | CDC Growth Charts | Weight-for-age, Stature-for-age, BMI-for-age |
| Preterm babies (any age) | WHO + corrected age | Use corrected age until 24–36 months corrected |
Source: American Academy of Pediatrics, 2010 Clinical Report on the Use of World Health Organization and CDC Growth Charts
What About BMI?
The WHO Body Mass Index chart covers 0–5 years. The CDC BMI-for-age chart covers 2–20 years. For children between 2 and 5, either can be used — most US clinics transition to CDC at age 2 for consistency, since the CDC charts carry through to adulthood.
BMI-for-age thresholds in children differ from adult BMI:
- Underweight: below 5th percentile
- Healthy weight: 5th–84th percentile
- Overweight: 85th–94th percentile
- Obese: 95th percentile and above
Asking the Right Questions at Your Next Visit
You don't need to audit your pediatrician's software, but it's reasonable to ask:
- "Which growth chart are you using for my baby?"
- "Is my baby's trend consistent, or have they crossed percentile lines?"
- "Can I see where they're plotted?"
Most modern electronic health record systems (Epic, Cerner) have largely switched to using WHO charts for under-2 and CDC for over-2, consistent with AAP guidance. But practices vary, especially in older or smaller clinics.
Baby Weight Percentile Calculator
Uses WHO data to calculate your baby's weight percentile from birth to 24 months — the same standard your pediatrician should be using.
The Bottom Line
| WHO | CDC | |
|---|---|---|
| Ages 0–2 | ✅ Recommended | ❌ Not recommended |
| Ages 2–20 | ✅ Use for 2–5 if preferred | ✅ Standard for US clinics |
| Breastfed babies | ✅ Best match | ⚠️ May underestimate adequacy |
The WHO chart isn’t “better” than the CDC chart in absolute terms — it’s just the right tool for the right age group. A reference built from optimally-fed children is the right benchmark for a baby you’re trying to feed optimally. For the full context on how those standards were developed, understanding WHO child growth standards explains the methodology behind the reference population.
Baby Height Percentile Calculator
Track your baby's length and height against WHO standards from birth through 5 years.
Frequently Asked Questions
Which growth chart does the AAP recommend?
The American Academy of Pediatrics recommends the WHO Child Growth Standards for children from birth through age 2, and the CDC Growth Charts for children ages 2 and older. This guidance was updated in 2010. Most US pediatric practices now follow this split recommendation.
Why does it matter which chart is used?
At certain ages — particularly 6–18 months — the WHO and CDC charts produce meaningfully different percentile values. A breastfed baby tracking at the 25th percentile on the CDC chart might be at the 40th percentile on the WHO chart. Using the CDC chart for infants can make breastfed babies look like slow gainers when they're actually growing exactly as expected.
Do WHO and CDC charts cover different age ranges?
Both cover 0–20 years. The WHO Child Growth Standards include charts from birth through 5 years (using 0–2 years for length-for-age, weight-for-age, and head circumference). The CDC Growth Charts cover birth through 20 years, with the recommended cross-over from WHO to CDC happening at age 2.
Are international babies measured on different charts?
The WHO charts were designed to be universal — they were built from children in Brazil, Ghana, India, Norway, Oman, and the United States under optimal conditions. They represent what healthy growth looks like globally, making them applicable across ethnicities and countries.
Medical Disclaimer
This article is for informational purposes only and does not constitute medical advice. Always consult your child's pediatrician or a qualified healthcare provider for any health-related concerns.Free Tools
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