The Effect of Substance Use in Pregnancy on the Risk of Infant Mortality

Abstract

Using data from the 1988 National Maternal and Infant Health Survey (NMIHS), this study examined the effect of maternal substance use during pregnancy on infant mortality in the United States. Logistic regression models were fitted to a 1988 cohort of births to study infant deaths. The results of the logistic regression models indicated that cigarette smoking and cocaine / crack use were associated with significantly higher risk of infant death. Mothers who smoked 1–19 cigarettes per day while pregnant were 38 percent more likely to experience infant mortality than nonsmokers. Heavy users of cocaine / crack were over twice as likely to have infant death as nonusers. Light cocaine users experienced a risk of infant mortality that was over three times that of nonusers. In general, alcohol consumption and marijuana / hash use in pregnancy had no significant effects on infant mortality. Analysis showed that while birth weight is the primary pathway by which cigarettes and cocaine / crack increase the risk of death, the two substances also affect mortality directly. It was concluded that while self-reports of substance use in the National Maternal and Infant Health Survey may to some extent be unreliable, the findings indicate that the true extent of substance use in pregnancy is underestimated. Relatedly, the finding of statistical significance on substance use despite the high rate of nonresponse illustrates that these substances have far more devastating consequences on infant mortality than those estimated in the analysis.