A Comparison of American and Chinese Intrauterine Growth Standards. Are American Babies Really Smaller?

Lin, Chia-Chin and I. Emanuel (School of Public Health and Community Medicine, Univ. of Washington, Seattle, Wash. 98195). A comparison of American and Chinese intrauterine growth standards. Are American babies really smaller? Am J Epidemiol 95: 418–430, 1972.—The relationship between birth weight and gestational age was studied for a series of 21,302 single liveborn Chinese babies from Taipei, Taiwan, and comparisons were made with various white American series, and with the white American population of newborns. While the Chinese babies as a group were substantially smaller than the American newborn population, gestational age-specific birth weights of the various American series were in general either within or below the confidence limits for the Chinese. Furthermore, the variation in gestational age-specific birth weights among the several American series was too large and was not of the pattern which would be expected on the basis of sampling error. It is suggested that none of the American fetal growth studies can be considered representative of the American population. Differences among the various American studies and the American population data can be attributed largely to methodological problems and regional variations in birth weight. The marked regional variation raises the question concerning the appropriateness of a single fetal growth standard for the entire country. This points to the need for the development of new and representative American intrauterine growth standards.