effects of nicotine alone derive primarily from animal studies, or can be inferred from the effects of smokeless tobacco, the striking similarity of findings in monkeys, mice, rats, sheep, and humans all support the direct effects of nicotine on lung development that mediate the deleterious effects of maternal smoking during pregnancy on offspring respiratory health.Limitations of this conclusion include a lack of comprehensive epidemiologic data on usage of e-cigarettes during pregnancy and limitations of animal models for asthma and SIDS.The effects of maternal smoking on lung development are mediated by nicotinic receptors, changes in airway geometry, effects on airway epithelial cell
proliferation, and oxidative mechanisms.Similarly, animal models show that the effects of prenatal nicotine exposure are also mediated by these same mechanisms.