“…The few existing studies that have specifically compared smokers who quit early in pregnancy (pregnancy quitters) with smokers who continued smoking during pregnancy (persistent pregnancy smokers) have shown significant differences in history of antisocial behavior between these groups (Wakschlag, Pickett, Middlekamp et al, 2003; Kodl & Wakschlag, 2004; Pickett, Wilkinson, & Wakschlag, 2009; McGrath et al, 2012). Importantly, while never smokers may differ from ever smokers, pregnancy quitters are also significantly different from persistent pregnancy smokers (Massey, Bublitz, Magee, et al, 2015, Massey, Estabrook, O’Brien et al, 2015). Broadly speaking, the continuum of never smokers, pregnancy quitters, and persistent pregnancy smokers may represent a continuum of risk.…”