Longitudinal Examination of Prenatal Tobacco Switching Behaviors and Birth Outcomes, Including Electronic Nicotine Delivery System (ENDS) and Dual Use

Introduction In the US, approximately 8% of pregnant women smoke, and 5–11.9% currently use ENDS products. The health effects of ENDS use are debated; however, most contain nicotine which is known to cause adverse perinatal outcomes. Studies have shown adult ENDS users significantly alter use behaviors over time (switch to conventional cigarettes-only or dual use) thus complicating efforts to examine health effects of ENDS use. The purpose of this study was to describe switching behaviors and associated birth outcomes among infants of women using conventional cigarettes only, ENDS-only, or both. Methods This was a multisite, longitudinal study of biologically confirmed perinatal tobacco users, with nicotine product use assessed each trimester. For the purpose of analysis, participants were defined as switchers, no-switchers, or quitters. Birth outcomes were abstracted from electronic medical records. Analysis included descriptive statistics, linear and multivariate logistic regression adjusted for age, preterm birth, smoking behavior in the first trimester, and an interaction between smoking switching behavior and smoking behavior in the first trimester. Analysis was conducted using SAS v9.4 with significance determined as p < 0.05. Results At enrollment, 48.6% of participants used only conventional cigarettes, 41.7% were dual users, and 10% used ENDS-only. While almost two-thirds of participants used the same tobacco product throughout pregnancy, 26% reported switching behaviors that were complex and not easily clustered. No differences were found in birth outcomes between switchers and no-switchers; however, a difference emerged in birth weight between no-switchers and quitters. Discussion Given the limited data on health effects of ENDS use, and the known harmful consequences of perinatal nicotine use, capturing and classifying product switching behaviors is imperative to inform public health, and remains a challenge requiring further research.