Growth of Japanese breastfed infants compared to national references and World Health Organization growth standards

Aim The aim of this study was to compare the growth of Japanese infants that were exclusively breastfed to those of national references and World Health Organization (WHO) standards. Methods Mothers, who delivered a normal term baby and had been exclusively breastfeeding for at least 4months, were enrolled. The lengths, body weights and head circumferences of 647 children, aged 0-24months, were obtained and compared to national references and WHO standards. Results Comparisons of the national references for both length and body weight indicated that breastfed infants were significantly shorter and lighter almost throughout the first 24months. Conversely, head circumferences of breastfed infants were significantly larger at 1 and 6months of age in boys and 6months in girls. Compared to WHO standards, similar trends to the comparisons with national references were found. Conclusion There were significant differences identified between the growth of breastfed infants and existing national references and WHO standards.