1986 a statistical evaluation showed that 21% of women in Austria smoked. This means an increase since 1972 of 13%. Also smoking during pregnancy shows a distinct increase. Smoking in pregnancy leads to a reduction of pulmonary function of the pregnant women and increases COHb in the blood of the fetus and newborn. Therefore a permanent state of oxygen deficiency is created which causes reduction of weight by 200 to 300 g in the newborn infant. An increased number of necrotic areas in the placenta are found. Concerning all these facts smoking should be stopped at the beginning of pregnancy and the pregnant women should be informed by all means about the severe negative effects of smoking in pregnancy.