Maternal Smoking During Pregnancy and Infant Infectious Disease Morbidity and Mortality
Purpose: Maternal smoking is associated with infant respiratory infections and with increased risk of low birthweight (LBW) infants and preterm birth. This study assesses the association of maternal smoking during pregnancy with both respiratory and non-respiratory infectious disease (ID) morbidity and mortality in infants.
Methods: We conducted two retrospective case-control analyses of infants born in Washington State from 1987-2004 using linked birth certificate, death certificate, and hospital discharge records. The first analysis assessed morbidity—infants hospitalized due to ID within one year of birth (47,404 cases/48,233 controls). The second assessed mortality—infants who died within one year due to ID (627 cases/2,730 controls).
Results: Maternal smoking was associated with both hospitalization (Adjusted Odds Ratio (AOR)=1.52; 95%CI: 1.46, 1.58) and mortality (AOR=1.51; 95%CI: 1.17, 1.96) due to any ID. In subgroup analyses, maternal smoking was associated with hospitalization due to a broad range of ID including both respiratory (AOR=1.69; 95%CI: 1.63, 1.76) and non-respiratory ID (AOR=1.27; 95%CI: 1.20, 1.34). Further stratification by birth weight and gestational age did not appreciably change these estimates. In contrast, there was no association of maternal smoking with ID infant mortality when only LBW infants were considered.
Conclusion: Maternal smoking is associated with a broad range of both respiratory and non-respiratory ID outcomes. Despite attenuation of the mortality association among LBW infants, ID hospitalization was found to be independent of both birthweight and gestational age. These findings suggest that full-term infants of normal weight whose mothers smoked may suffer an increased risk of serious ID morbidity and mortality.