Effects of Smoking on Unborn Babies.

• Research has shown that women’s smoking during pregnancy increases the risk of pregnancy complications, premature delivery, low-birth-weight infants, stillbirth, and sudden infant death syndrome (SIDS).

• The nicotine in cigarettes may cause constrictions in the blood vessels of the umbilical cord and uterus, thereby decreasing the amount of oxygen available to the fetus. Nicotine also may reduce the amount of blood in the fetal cardiovascular system.

• Nicotine is found in breast milk.

• Babies of mothers who smoked during pregnancy have lower birth weights. Low birth weight is a leading cause of infant deaths, resulting in more than 300,000 deaths annually among newborns in the United States.

• In general, pregnant smokers eat more than pregnant nonsmokers, yet their babies weigh less than babies of nonsmokers. This weight deficit is smaller if smokers quit early in their pregnancy.

• Smoking by the mother causes SIDS. Compared with unexposed infants, babies exposed to secondhand smoke after birth are at twice the risk for SIDS, and infants whose mothers smoked before and after birth are at three to four times greater risk.

• Mothers’ smoking during pregnancy reduces their babies’ lung function.

• In 2001, 17.5% of teenaged mothers smoked during pregnancy. Only 18% to 25% of all women quit smoking once they become pregnant.

• Children and adolescents who smoke are less physically fit and have more respiratory illnesses than their nonsmoking peers. In general, smokers’ lung function declines faster that that of nonsmokers.

• Smoking by children and adolescents hastens the onset of lung function decline during late adolescence and early adulthood.

• Smoking by children and adolescents is related to impaired lung growth, chronic coughing, and wheezing.

Source: United States Surgeon General's Office