Conclusions
Reduction of cigarette smoking among youths and pregnant women are 2 top public health prevention efforts in tobacco control. Despite progress toward Healthy People 2010 tobacco control objectives, targets for both of these groups remain unfulfilled. Our findings strengthen the evidence for intergenerational transmission of smoking phenotypes, supporting both physiological and genetic transmission through smoking during pregnancy as well as social role modeling of maternal smoking. They underscore the importance of prevention and intervention not only in pregnancy but also subsequent to birth, when relapse is common. Furthermore, they highlight the importance of halting or reversing youth trajectories in which smoking becomes highly prevalent by young adult childbearing ages.