When you’re pregnant, you take a lot of steps to ensure the health of your developing baby. You eat all the right foods and exercise daily. You get plenty of rest and try to reduce your stress levels. And you make sure not to miss a single prenatal appointment. But if you’re addicted to cigarettes, stopping smoking is one of the most significant things you can do to deliver a healthy baby. According to a survey by the U.S. Public Health Service, nearly 20 percent of women smoke while pregnant. Unfortunately, the harmful compounds found in cigarettes can impair, and even be fatal to, a developing fetus.
Carbon monoxide and nicotine, two of the most toxic of the thousands of compounds and substances found in cigarettes, are the main sources of the negative effects on an unborn child. When combined with hemoglobin, carbon monoxide forms a harmful compound called carboxyhemoglobin. This new compound robs the fetus of vital oxygen. Likewise, nicotine, which acts as a vasoconstrictor to narrow blood vessels, diminishes the placenta’s ability to pass oxygenated blood to the baby. In addition, nicotine passes through the amniotic to directly affect the baby’s immature cardiovascular and central nervous system.
Because of nicotine’s constrictive properties on blood vessels and reduced blood flow to the placenta as a result, women who smoke are at a slightly greater risk for spontaneous abortion than non-smokers. In fact, a study by the California Department of Health Services revealed that women who smoke an average of 20 cigarettes a day are especially at risk after the first trimester. But these findings are not new. A researcher named Ballantyne noted as early as 1902 that the incidence of miscarriage was greater for pregnant women working in tobacco factories than for those who did not.
Placental Abruption and Previa
Smoking also poses a risk to the heath and function of the placenta, the organ through which oxygen and nutrients pass from the mother to the fetus. Smoking causes a higher incidence of placental abruption, the detachment of the placenta from the uterine wall. Placental abruption is a serious medical emergency that can lead to vaginal bleeding, premature birth of the fetus and even fetal death. Placenta previa is another serious condition in which the placenta attaches low on the uterine wall, presenting before the baby, instead of after, the birth.
Delayed Fetal Growth
Babies born to smokers are, on average, up to 1 pound lighter in weight and shorter in length than those born to non-smokers. Researchers have not been able to confirm the reasons for this, but it is thought that it is due to both the decrease in oxygenated blood and nutritional supply to the placenta. And because smoking stunts the maturity of the cardiovascular and central nervous system, decreasing the supply of oxygen to the brain, it’s suspected that a mother’s smoking plays a role in behavioral and learning disorders that might later develop, even if the baby is otherwise healthy.
Fetal mortality after 20 weeks gestation rises to as much as 35 percent for pregnant women who smoke, according to a study by the Ontario Perinatal. But even after the baby is born, its distressed central nervous system can impair the lungs’ function and lead to fetal hypoxia. Basically, the baby cannot receive the oxygen it needs and suffocates. Maternal smoking is the leading factor in all SIDS-related deaths.
Pathogens found in cigarettes cross over the placental membrane and imbed in the tissues of the developing fetus. While the compounds found directly in cigarettes and indirectly in cigarette smoke increase the risk of all cancers, this is especially true of acute lymphocytic leukemia.