Recommended Growth Charts for Infants and Toddlers
Use the WHO growth charts from birth until 24 months of age, then transition to CDC growth charts from 24 months (2 years) through 19 years of age. 1
Evidence-Based Recommendation
The CDC, in collaboration with the National Institutes of Health and the American Academy of Pediatrics, formally recommends this two-chart approach based on a 2006 expert panel review. 1 This represents the current standard of care in the United States for establishing growth trends in young children.
Birth to 24 Months: WHO Growth Charts
The WHO 2006 international growth standards should be used for all children under 24 months of age. 1 The rationale for this recommendation includes:
Breastfeeding as the standard: The WHO charts are based on healthy breastfed infants (100% breastfed for 12 months, predominantly breastfed for at least 4 months), which aligns with the recognized standard for infant feeding. 1
Growth standards vs. growth reference: Unlike the CDC charts which describe how certain children grew in a specific population, the WHO charts represent optimal growth under ideal conditions—functioning as true standards rather than references. 1
International validity: The WHO charts demonstrate remarkably consistent growth patterns across different countries and ethnic groups when children receive optimal nutrition. 2
24 Months to 19 Years: CDC Growth Charts
Switch to CDC 2000 growth charts at 24 months and continue through age 19 years. 1 The justification includes:
Methodological similarity: After 24 months, the methods used to create WHO and CDC charts are similar, making this an appropriate transition point. 1
Continuity of care: The CDC charts extend through age 20 years, allowing continuous monitoring throughout childhood and adolescence without further chart changes. 1
Practical measurement alignment: The transition at 24 months coincides with the change from recumbent length to standing height measurements. 3
Important Clinical Considerations
Screening Thresholds
For WHO charts (under 24 months): Use the 2.3rd and 97.7th percentiles (±2 standard deviations) rather than the traditional 5th and 95th percentiles to identify potentially abnormal growth. 1
For CDC charts (24 months and older): The 5th and 95th percentiles are typically used as cutoff points. 3
Common Pitfalls to Avoid
Breastfed vs. formula-fed infants: Clinicians should recognize that breastfed infants typically show slower weight gain between 3-18 months compared to formula-fed infants, and this is normal on WHO charts. 1 Formula-fed infants tend to gain weight more rapidly after approximately 3 months and may cross upward in percentiles. 1
The transition disjunction: Be aware that switching from WHO to CDC charts at age 2 years creates a slight discontinuity in how a child's growth is classified. 1, 4 Recent research suggests this abrupt switch can cause clinically important changes in growth z-scores even in children with stable growth patterns, potentially leading to overidentification of slow weight gain. 4
Interpretation context: Growth patterns over time using multiple serial measurements should be used in conjunction with medical and family history to assess appropriate growth—single data points are insufficient. 1
Training Requirements
Healthcare providers require training on accurate measurement techniques (especially recumbent length), interpretation of growth standards versus references, and understanding the characteristics of the WHO cohort to properly apply these charts. 1
Why Other Options Are Incorrect
AAP growth curves: The AAP endorses the WHO/CDC approach described above, not separate AAP-specific growth curves. 1
Fenton growth charts: These are specifically designed for preterm infants and are not the standard recommendation for term infants and toddlers. 1
CDC charts for first 7 years: This contradicts the evidence-based recommendation to use WHO charts for the first 24 months. 1