A population based case control study was conducted to examine alcohol consumption and maternal smoking during pregnancy and the risk of SIDS in an Irish population. Each SIDS case (n=287) was compared with control infants (n=832) matched for date and place of birth for infants born from 1994 to 2001. Conditional logistic regression was used to investigate differences between Cases and Controls establishing Odds Ratio’s (OR) and 95% Confidence Intervals (CI). Mothers who smoked were 3 times more likely to have a SIDS Case, and a dose response effect was apparent, with mothers smoking 1-10 cigarettes/day OR 2.93 (CI 1.50-5.71), and those smoking >10 cigarettes/day OR 4.36 (CI 2.50-7.61).

More Case mothers consumed alcohol during pregnancy than Control mothers and, within drinkers, the amount of alcohol consumed was also greater (p<0.05). A dose response with frequency of drinking was apparent. The adjusted odds ratio for those consuming alcohol in all three trimesters was 3.59 (CI:1.40-9.20). Both of these risk factors are modifiable and need to be incorporated into antenatal education from a SIDS point of view.