Growth Assessment for Infants

Introduction to Growth Charts

The World Health Organization (WHO) recommends using its international growth charts for assessing the growth of all children under 24 months, regardless of feeding type 2
These charts represent an optimal growth standard, based on healthy children who were predominantly breastfed for at least 4 months and were still being breastfed at 12 months 2
For children aged 24-59 months, the Centers for Disease Control and Prevention (CDC) growth charts are recommended 2

When using the WHO growth charts, it is recommended to consider values of 2 standard deviations above and below the median (percentiles 2.3 and 97.7, labeled as percentiles 2 and 98 in the growth charts) 2, 3
These measurements are useful for identifying children whose growth may be indicative of adverse health conditions 2
The WHO charts have less variability than the CDC charts for children under 24 months, which may lead to a higher prevalence of identification of both low and high stature when applying the percentiles 3

The WHO charts are based on a high-quality study (MGRS) with longitudinal data collected more frequently than the data used for the CDC charts, especially during the first months of life when children grow more rapidly 4, 5
The CDC charts for children under 36 months were based on cross-sectional data from various sources, with a scarcity of data for the first months of life 1, 4
At 2 months of age, the CDC charts were based on only 72 weight measurements (38 boys and 34 girls) 4, 5

Physicians should recognize that the WHO charts are intended to reflect the optimal growth of infants and children 2
Although many children may not have experienced the optimal environmental, behavioral, or health conditions specified in the WHO study, the charts are intended to be used with all children under 24 months 2
The growth of some children may not always follow the patterns shown in the WHO curves, especially formula-fed children, who tend to gain weight more quickly 2

Deviations from the expected height can indicate underlying health problems and require further evaluation 2, 3
The CDC recommends using modified versions of the WHO curves for children under 24 months that include the 2.3 and 97.7 percentiles and are suitable for physicians 2, 6