smoke is particularly dangerous for pregnant women and their children. All the poisons from cigarette smoke that enter a mother's blood are passed along to her fetus. The carbon monoxide reduces the amount of oxygen in the unborn baby's blood. That is why babies of smokers are more likely to be born with low birth weights (less than 5 1/2 pounds) and birth defects. Each year 53,000 babies are born under weight. They are sometimes born prematurely (before 9 months) or even born dead (stillbirth). Smoking also increases a woman's chance of having a miscarriage by 24%.