[Unexpected and unexplained infant death. Epidemiologic and comparative study of Belgian and immigrant populations].

The medical records of 299 Belgian and immigrant children who died between 15 days and one year in the years 1970-1977 have been analysed. Fifty two died of congenital malformations, 119 of major infections and 128 died suddently for no obvious reason; neither the clinical history nor the laboratory data would account for death. In both the Belgian and immigrant population the children who died suddenly and unexpectedly did not differ from the other groups of children who died in respect of social class, mother's age at delivery, her parity and medical history, the baby's gestational age, birth weight and Apgar score, the method of feeding, the physical growth or psychomotor development. Infection is not more frequent in the week before death and there is no seasonal variation. The majority of unexpected deaths occur between 2 and 4 months of age and the child is most often discovered between 6 and 12 a.m. These characteristics are also observed in children who die of sudden infant death syndrome.