A study of infant mortality and its components was carried out in a cohort of live born children from hospitals of Ribeirão Preto, city of São Paulo, Brazil, whose mothers were interviewed shortly after deliverance. Mortality was associated to social classes and birthweight. The uneven distribution of mortality showed that social classes acted as distinct populations and that birthweight was not the only cause of this unballance. Lower social classes were associated with higher low birthweight rates and mortality coefficients. The study of infant mortality without taking into account the social differences may show coefficients that underestimate the magnitude of the problem among the poorest population segments.
Birthweight; Social Class; Infant Mortality
