4. New Features of the CDC Growth Charts

Although the CDC Growth Charts appear similar to the 1977 NCHS charts, they differ in several important ways. First, the data used to construct the new charts included a nationally representative reference population of infants from birth to 36 months and of children and adolescents from 2 to 20 years of age. Second, improved statistical smoothing methods were used to fit the data from national surveys to create smooth curves.

Additionally, there are several clinically significant new features of the charts that include:

	BMI-for-age charts for children and adolescents age 2 to 20 years
	The 85th percentile to identify at risk of overweight added to the BMI-for-age chart and weight-for-stature chart
	The 3rd and 97th percentiles added to specific charts
	The limits for length and height were lowered   On the weight-for-length chart for children from birth to 36 months old, length was extended from 49 to 45 cm. On the optional weight-for-stature chart, the extension from 90 to 77 cm allows almost all 2-year-old children to be plotted on the chart.
	Smoothed percentile curves and z-scores agree
	Correction in the disjunction that occurred between 24 and 36 months of age when switching from length to stature using the 1977 NCHS growth charts.