Intrapartum Electronic Cigarette Use and Birth Outcomes: Evidence from a Population-Based Study.

The harms of combustible cigarette (CC) use in pregnancy for fetal development are well studied. Less understood are the potential impacts of newer non-combustible cigarette alternatives, including electronic cigarettes (ECs). Our goal was to examine whether EC use during pregnancy predicts increased risk of adverse birth outcomes. This retrospective cohort study used data from the Obstetrics Initiative (OBI), a statewide collaborative of 70 maternity hospitals. OBI's clinical registry of data on nulliparous, term, singleton, and vertex fetal presentation pregnancies were from medical records. Three groups of pregnancy cigarette users (Controls (n = 26,394), CC (n = 2216), and EC (n = 493)) were compared on birth outcomes, controlling for background differences. Controls were defined as nonsmokers of ECs or CCs. Compared to the controls, the EC group had significantly lower birth weight, while the CC group had reduced birthweight and greater rates of arterial cord pH < 7.1. Compared to EC users, CC users had higher rates of neonates requiring antibiotics and NICU admission. Growing evidence suggests ECs are not safer alternatives to CCs and use during pregnancy should be discouraged. Additional research is needed, as non-significant trends for increased risk of several adverse neonatal outcomes following EC use were found, potentially significant in larger studies with average risk for adverse pregnancy outcomes and when frequency and timing of EC exposure are considered.