The purpose of this study is to assess the risk of poor birth outcomes in individuals who use electronic cigarettes before and during pregnancy. Data from the 2016–2018 PRAMS were used to examine the relationship between e-cigarette use in the three months preceding and three months following pregnancy among 79,176 people who had a recent live birth and the following birth outcomes: preterm birth, small for gestational age, and low birth weight (LBW). Using average marginal predictions from multivariable logistic regression models, adjusted prevalence ratios were calculated. Prenatal combustible cigarette smoking and e-cigarette usage were used to stratify the models. 2.7 percent of respondents used e-cigarettes in the three months preceding pregnancy, and 1.1 percent used e-cigarettes in the final three months of pregnancy. The usage of electronic cigarettes before pregnancy was not linked to poor birth outcomes. When compared to nonusers, electronic cigarette usage during pregnancy was related with an increased prevalence of LBW. E-cigarette usage was related with a greater frequency of LBW and preterm delivery among respondents who did not simultaneously smoke combustible cigarettes during pregnancy. Only for daily e-cigarette users were relationships seen when stratified further by frequency of e-cigarette usage.

E-cigarette usage during pregnancy, particularly when used on a regular basis by those who do not concurrently smoke combustible cigarettes, has been linked to poor birth outcomes.