Aim: To evaluate the performance of the 2000 Centers for Disease Control and Prevention (CDC) growth charts in comparison with the National Center for Health Statistics/World Health Organization (NCHS/WHO) reference as a tool for assessing growth in healthy breastfed infants. Methods: Weight and length measurements were obtained from a pooled longitudinal sample of 226 healthy breastfed infants. Weight-for-age (WA), length-for-age (LA) and weight-for-length (WL) z-scores based on the CDC and NCHS/WHO references were computed for each child. Age-specific mean z-scores and proportions below and above specific cut-off points were calculated. Results: Breastfed infants grow more rapidly in the first 2 mo of life and less rapidly from 3 to 12 mo in relation to the CDC WA curves. Similarly, breastfed infants experience greater linear growth than the CDC median until age 4 mo. Thereafter, the mean LA z-score declines until month 9. Apart from a 1-mo difference in the time when linear growth begins to falter, the pattern of growth is remarkably similar when compared with the two references. The growth trajectories indicate that infants in the CDC reference are heavier and shorter than the NCHS/WHO reference population. Combining the two measurements as WL reveals that higher weight overrides lower length in the CDC versus the NCHS population, thus the estimated prevalence of wasting is higher by the CDC reference.
Conclusion: As was the case when compared with the NCHS/WHO reference, there are notable differences in the growth trajectory of breastfed infants examined against the CDC reference. A reference based on healthy breastfed infants is required if the growth patterns of infants following international feeding recommendations are to be correctly assessed.