Creating the WHO Growth Standard for Infants and Young Children
In 1993, WHO established a working group on infant growth to conduct a comprehensive review of the uses and interpretation of the 1977 National Center for Health Statistics (NCHS)/WHO growth reference, which had been recommended for international use since the late 1970s.1
The experts on the working group concluded that
- New growth curves were needed to replace the existing international reference, which had numerous limitations making it inappropriate for assessing the growth pattern of individual children and populations.2
- A standard rather than a reference was needed to describe how children grow in all countries rather than how they grew in a specific place and time.3
- A standard was needed to emphasize the importance of ensuring that the new growth charts were consistent with the growth of infants under the “best” health conditions such as being exclusively breastfed for at least 4 months and born to a mother who does not smoke during pregnancy and lactation.
The outcome of the recommendations was the WHO Multicenter Growth Reference Study (MGRS) on which the WHO growth standards are based.
WHO Multicenter Growth Reference Study (MGRS)
The MGRS was conducted from 1997 to 2003 in six sites (Pelotas, Brazil; Accra, Ghana; Delhi, India; Oslo, Norway; Muscat, Oman; and Davis, California) to generate new growth curves to assess growth of infants and young children throughout the world.
A primary study hypothesis was that infants and young children have the potential to grow similarly, regardless of their race/ethnicity and place of birth, if they are breastfed, living in a healthy environment, and have adequate nutrition.
This hypothesis of similar growth was confirmed as the mean length measurements from birth up to 24 months in the 6 country sites were virtually identical.
1 Garza C and de Onis M. Rationale for developing a new international growth reference. Food Nutr Bull 2004;25 Suppl1:S5-14.
2 de Onis M, Garza C, Onyango AW, Borghi E. Comparison of the WHO child growth standards and the CDC 2000 Growth Charts. J Nutr 2007;137(1):144-148.
3 WHO Multicentre Growth Reference Study Group. Enrolment and baseline characteristics in the WHO Multicentre Growth Reference Study. Acta Paediatr Suppl. 2006;450:7-15.