Smoking and pregnancy.

Smoking during pregnancy is associated with many adverse outcomes, including fetal and neonatal death. These consequences are tragic in many ways, but perhaps the greatest tragedy is that they are preventable if the smoker ceases to smoke during pregnancy. Although in some instances the so-called constitutional hypothesis is difficult to disprove, the available evidence seems more than convincing that it is smoking itself, and not the smoker's unique constitution, that is responsible. Cessation from smoking is clearly advisable at any time, but more so during pregnancy when every cigarette affects both the smoker and her unborn child.