Smoking and Pregnancy: An unhealthy combination Genetic Matters

Chemicals, drugs, physical agents and any other environmental factors that can cause birth defects in babies are called teratogens. The term teratogen is from the Greek word for monster. Many teratogenic substances are capable of passing from mother’s circulation, through the placenta and into the developing baby’s bloodstream. It is important to note that these types of birth defects are preventable if exposure is avoided.

A 1998 study by the Centers for Disease Control (CDC) revealed that 22 million women 18 years and older in the United States smoke cigarettes. It is estimated that approximately 1.5 million adolescent females are also smokers.

There are more than 4000 identified chemical compounds in tobacco smoke; more than 40 are known to be carcinogenic or cancer-causing. Two of the most studied compounds in terms of biologic effects are nicotine and carbon monoxide. The effects of nicotine are to constrict blood vessels resulting in increased blood pressure and heart rate. A strong attraction between hemoglobin and carbon monoxide results in decreased oxygen levels in cells and tissue.

What does it mean to a developing fetus if mother smokes? The single most apparent effect is low birth weight, usually less than 2500 grams or 5.5 pounds. Nicotine constricts the blood vessels of the placenta causing reduced blood flow to the fetus. Mothers who smoke are at increased risk for placental abnormalities. The risk of miscarriage, stillbirth, or death of a newborn is about 30% higher for women who smoke during pregnancy. Carbon monoxide adds to the oxygen deprivation to the fetus and may result in delayed development.

As a group, studies have shown that children of mothers who smoke are at increased risk for learning delays and behavior difficulties. These children are also more likely to have health concerns and more doctor visits primarily for upper respiratory infections.

It is estimated that 20-25% of women in the United States smoke cigarettes during pregnancy. It is strongly advised that women not smoke during their pregnancies, but if quitting is impossible, to at least significantly reduce the practice.

There are few things that are 100% preventable but birth defects due to smoking by mothers is one.