Describe the effects of smoking, alcohol consumption, and excessive caffeine consumption on the growth and development of the fetus

Answer 1

Constituents of cigarette smoke, such as nicotine, carbon monoxide, arsenic, and cyanide, are toxic to a fetus. Smoking during pregnancy can cause damage to fetal chromosomes, which could lead to developmental defects or diseases such as cancer. Smoking also restricts the blood supply to the growing fetus and so limits the delivery of oxygen and nutrients and the removal of wastes. It slows fetal growth, can reduce brain size, and may impair the intellectual and behavioral development of the child later in life. Smoking during pregnancy damages fetal blood vessels, an effect that is still apparent at the age of 5 years. It interferes with fetal lung development and increases the risks of respiratory infections and childhood asthma. A mother who smokes is more likely to have a complicated birth and a low-birthweight infant. The more a mother smokes, the smaller her infant will be. Of all preventable causes of low birthweight in the United States, smoking has the greatest impact. Sudden infant death syndrome (SIDS), the unexplained death that sometimes occurs in an otherwise healthy infant, has also been linked to the mother's cigarette smoking during pregnancy. Even in women who do not smoke, exposure to environmental tobacco smoke (ETS, or secondhand smoke) during pregnancy increases the risk of low birthweight and the likelihood of SIDS.

Drinking alcohol during pregnancy threatens the fetus with irreversible brain damage, growth retardation, mental retardation, facial abnormalities, vision abnormalities, and many more health problems—a spectrum of symptoms known as fetal alcohol spectrum disorders, or FASD. Children at the most severe end of the spectrum (those with all of the symptoms) are defined as having fetal alcohol syndrome (FAS), which results in facial abnormalities. Less obvious is the internal harm: The fetal brain is extremely vulnerable to a glucose or oxygen deficit, and alcohol causes both by disrupting placental functioning. The lifelong mental retardation and other tragedies of FAS can be prevented by abstaining from drinking alcohol during pregnancy. Once the damage is done, however, the child remains impaired. An estimated 5 to 20 of every 10,000 children are victims of FAS, making it one of the leading known preventable causes of mental retardation in the world.

Caffeine crosses the placenta, and the fetus has only a limited ability to metabolize it. Research studies have not proved that caffeine (even in high doses) causes birth defects in human infants (as it does in animals), but limited evidence suggests that heavy use—intake equaling more than 3 cups of coffee a day—increases the risk of hypertension and miscarriage. Depending on the quantities consumed and the mother's metabolism, caffeine may also interfere with fetal growth. Lower doses of caffeine appear to be compatible with healthy pregnancies. All things considered, it may be most sensible to limit caffeine consumption to the equivalent of one or two cups of coffee a day.