Associate Professor State University of New York at Buffalo Buffalo, New York, United States
Background: Electronic cigarettes (e-cigarettes) have been increasingly used, while combustible cigarettes have been decreasingly used among pregnant people, partially due to the harm reduction perception. Objective: We aimed to investigate the impact of maternal e-cigarette use on infant mortality. Design/Methods: We analyzed secondary data from the U.S. Pregnancy Risk Assessment Monitoring System (PRAMS, 2016-2021, N=233,642). Mothers were stratified into 4 groups based on self-reported e-cigarette and cigarette use status during the last 3 months of pregnancy: (exclusive) e-cigarette users, (exclusive) combustible cigarette users, dual-users of e-cigarettes and cigarettes, and non-users. Infant deaths up to 6 months of age were obtained from questionnaire surveys. We used multivariable logistic regression to examine the associations between maternal e-cigarette/cigarette use and infant mortality, as well as the mediation roles of two adverse birth outcomes (small-for-gestational-age [SGA] birth and preterm birth). Results: The majority of mothers were non-users (91.1%) during late pregnancy, followed by cigarette users (7.4%), dual users (0.8%), and e-cigarette users (0.7%). Cigarette users (0.87%; confounder-adjusted odds ratio [aOR]=1.85 [95% confidence interval, 1.39-2.45]; p-value < 0.001), but not e-cigarette users (0.54%; 1.38 [0.57-3.34]; p-value=0.482) or dual users (0.40%; 1.02 [0.39-2.68]; p-value=0.962), had a significantly higher infant mortality, compared with non-users (0.42%). The association between maternal cigarette use and infant mortality was partially mediated by SGA (aOR attenuated to 1.76 [1.28-2.41]; p-value < 0.001) or preterm birth (aOR attenuated to 1.55 [1.15-2.08]; p-value=0.003).
Conclusion(s): In this U.S. cohort, exclusive cigarette use during late pregnancy is a risk factor for infant mortality, which is partially explained by smoking-related SGA and preterm birth. Exclusive e-cigarette use or dual use is less likely to play a critical role in infant mortality.
