We aimed to estimate exposure-response associations between smoking or vaping, and preterm and small-for-gestational age (SGA) births. We included 99,201 mothers who delivered live singletons in 2016-2018 from the Pregnancy Risk Assessment Monitoring System. We created exposure categories based on participants' self-reported average number of cigarettes smoked per day and vaping frequency. Dual users in late pregnancy were a heterogeneous group: 36% heavily smoked and occasionally vaped; 29% lightly smoked and frequently vaped; 19% lightly smoked and frequently vaped; and 15% both heavily smoked and frequently vaped. While dual users who heavily smoked and occasionally vaped had the highest adjusted OR for SGA (3.4, 95% CI 1.7-6.6), all the dual users were on average at about twice the odds of having SGA than non-users. While the risks of preterm birth were higher among sole light smokers (adjusted OR 1.3, 95% CI 1.1-1.5) and sole heavy smokers (adjusted OR 1.4. 95 CI 1.2-1.8) than non-users, the adjusted odds of preterm births for dual users were not noticeably higher than those of non-users, unless they were also heavy smokers. Excess of preterm births among heavy vapers was suggested. Among younger non-Hispanic white women (where vaping is most common), only excess risk of SGA, not preterm, with vaping was apparent. Relative to non-users, both smoking and vaping during pregnancy appear to increase risk of SGA, but excess risk of preterm births appears to be primarily attributable to smoking alone. Higher levels of exposure tended to confer more risk.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.