The association between maternal smoking and retarded maternal condition and birth outcome is well know. Smoking during pregnancy increases risk of spontaneous abortion, placenta previa, abruptio placenta, preterm premature rupture of membranes, stillbirth, preterm delivery and sudden infant death syndrome. The recently conducted studies also indicate that prenatal exposure to tobacco smoke is a risk factor for respiratory infections, asthma, allergy, childhood cancer, and it has neurobehavioral consequences regarding children's health. The risk for most of these conditions has been found to increase with the number of cigarettes smoked. On the other hand women who stopped smoking during pregnancy are at lower risk for most of those pathologies.