One of the strengths of the current study is that it used standard criteria for evaluating all potential SIDS deaths, making it easy to compare details among the cases. In prior studies, the SIDS cases sometimes had been evaluated under a number of different standards. Similarly, the researchers conducted an extensive investigation of the death scene that involved asking the infants' caregivers detailed questions. These included questions about: the events preceding the infant's death, discovery of the deceased infant, the medical history of the infant and family, as well as maternal alcohol, tobacco, and drug abuse before and during pregnancy.
The study relied primarily on the ability of mothers and family members to recall events regarding the infant's last sleep. The study authors noted that mothers who had lost their infants to SIDS may have been better able to recall the circumstances surrounding their infant's last sleep than were the mothers of the control infants. The study authors do not believe this possibility is likely, however, as both cases and controls were interviewed within a short time of their infants' last sleep period.
Source: Press Release, National Institute of Child Health and Human Development