International collaborative effort (ICE) on birth weight, plurality, perinatal, and infant mortality. III: A method of grouping underlying causes of infant death to aid international comparisons.

Underlying causes of infant death, as coded in the ninth revision of the International Classification of Diseases, have been grouped into a system of seven functional categories plus one additional group of "other and unclassifiable" diagnoses. The groups comprise congenital anomalies, asphyxia related conditions, immaturity related conditions, infections, sudden death, deaths due to external causes, and other specific conditions. The groups were constructed by using a frequency distribution of underlying cause of death in 200,000 infant deaths in 1980-84 in the U.S.A. When analysed according to age at death and according to birth weight, the distribution of the functional groups had patterns which corresponded to what might be expected clinically. Each functional group has common features which require intervention at a specific time for prevention and treatment. We propose that it is used as a tool in epidemiological surveillance and to guide health authorities in priorities for disease control. International comparisons of time trends will be undertaken.