2. Substance abuse

Substance abuse during pregnancy poses a threat to the health and well-being of both the mother and her unborn child. It is difficult to know exactly how many women abuse alcohol and drugs during their pregnancies, but the problem is clearly of concerning size. About 15% of women who present for prenatal care have been shown to have a positive urine test for one or more of the following: alcohol, marijuana, cocaine, and opiates (such as heroin).

This is worrisome not only because almost every substance of abuse freely crosses the placenta into the fetus but also because of the risky behaviors which can be associated with substance abuse, including unsafe sex, exchanging sex for drugs and money, and engaging in physically unsafe behavior.

1. Tobacco smoke

Tobacco smoke is a highly complex substance containing many possibly harmful ingredients including nicotine, tar, carbon monoxide, and cyanide. All of these appear to contribute to the health problems affecting mothers who smoke, including respiratory illnesses, peptic ulcer disease, esophageal reflux, and in the long term, cancer.

Nicotine is particularly problematic during pregnancy because it tends to make blood vessels constrict which causes there to be less blood flow to the placenta which translates into less oxygen and nutrients for the fetus. In addition to decreasing blood flow, smoking can lead to a complication called placental abrupt ion, a condition in which the placenta detaches from the wall of the uterus before the fetus is ready to be born. One in 500 cases of severe abrupt ion leads to fetal death.

In general, smoking is associated with an increased frequency of miscarriage with the risk of miscarriage is increased 1.2 fold for every 10 cigarettes smoked. A report by the Surgeon General in 1983 estimated that 4600 infants died each year in the United States as a result of smoking during pregnancy.

Babies of smokers also tend to be born prematurely and to have lower birth weights with birth weight reduction being directly related to the number of cigarettes smoked each day.

Increased rates of neonatal death and of the sudden infant death syndrome (SIDS) have also been observed. The long-term effects of smoking are still under investigation, but smoking during pregnancy has been associated with impaired growth after birth, impaired intellectual development, and behavioral disorders including hyperactivity and attention deficit disorders.

(The material presented here has been adopted from a pamphlet written and distributed by the American College of Obstetricians and Gynecologists.)