Previous fetal loss and risk of sudden infant death syndrome in subsequent offspring.

The relationships between previous fetal loss (obtained by mother's statement) and certain categories of infant death including probable instances of the sudden infant death syndrome (SIDSp) were examined. The deaths were those occurring among the cohort of live singleton births born in the State of North Carolina, 1960-1967. SIDSp were defined by age (28-364 days), place of death (outside the hospital), and certain ICD code numbers of the 7th Revision (273, 331, 422.2, 491-493, 500-501, 522, 525, 527.2, 762, 795 and 924). Other deaths in the postneonatal period were dichotomized between congenital malformations (ICD 750-759) and all other causes combined. Neonatal deaths were classified as due to either congenital malformations or other causes. For neonatal deaths and for all categories of deaths other than SIDSp in the postneonatal period there was a strong tendency for the standardized mortality ratios (SMR) to increase with increasing history of previous fetal loss. This was true for blacks and whites, and for both mothers under and over 25 years of age. The SMR for SIDSp, on the other hand, suggested an opposite association among blacks and little association among whites. Overall there was a significant difference between the patterns for SIDSp and all other postneonatal causes of death combined.