Other Characteristics of the Growth Reference
VLBW Infants Growth Patterns
Here you see the 50th and 5th percentiles of length-for-age and weight-for-age for girls for both the IHDP growth reference for VLBW infants (dashed lines) and the CDC Growth Charts (solid lines). This comparison suggests that VLBW infants included in the IHDP reference have rapid linear growth allowing them to nearly catch up with the infants in the CDC reference for length-for-age by 24 months of age. Whereas, in weight-for-age, the very low birth weight infants in the IHDP reference have less rapid growth resulting in their being thinner than the infants in the CDC reference.
Regardless of which reference is used, the child's gestation-adjusted age at birth must be determined before plotting. The gestation-adjusted age should continue to be used for all plots up to 24 months of age.