Fetal Alcohol Syndrome Health Article

Definition

Fetal alcohol syndrome (FAS) is a pattern of birth defects and learning and behavioral problems affecting individuals whose mothers consumed alcohol during pregnancy.

Description

FAS is the most common preventable cause of mental retardation. This condition was first recognized and reported in the medical literature in 1968 in France and in 1973 in the United States. Alcohol is a teratogen—the term used for any drug, chemical, maternal disease, or other environmental exposure that can cause birth defects or functional impairment in a developing fetus. Some features may be present at birth, including low birth weight, prematurity, and microcephaly. Characteristic facial features may be present at birth, or may become more obvious over time. Signs of brain damage include delays in development, behavioral abnormalities, and mental retardation, but affected individuals exhibit a wide range of abilities and disabilities. Only since 1991 has the long-term outcome of FAS been observed. Emotional disorders as well as learning and behavioral problems are common in adolescents and adults with FAS. Fetal alcohol effect (FAE), a term no longer favored, is sometimes used to describe individuals with some, but not all, of the features of FAS. In 1996 the Institute of Medicine suggested a five-level system to describe the birth defects, learning, and behavioral difficulties in offspring of women who drank alcohol during pregnancy. This system contains a number of criteria that must be present, including confirmation of maternal alcohol exposure, characteristic facial features, growth problems, learning and behavioral problems, and birth defects known to be associated with prenatal alcohol exposure.

The incidence of FAS varies among different populations studied, and ranges from approximately one in 200 to one in 2,000 live births. However, a study reported in 1997, utilizing the Institute of Medicine criteria, estimated the prevalence of FAS in Seattle, Washington, from 1975-1981 at nearly one in 100 live births. Avoiding alcohol during pregnancy, especially during the earliest weeks of the pregnancy, can prevent FAS. Not even the smallest amount of alcohol consumed during pregnancy has been proven to be completely safe.

FAS is neither a genetic nor inherited disorder. It is a pattern of birth defects and learning and behavioral problems that result entirely from maternal alcohol use during pregnancy. Alcohol freely crosses the placenta and causes damage to the developing embryo or fetus. Alcohol use by the father cannot cause FAS. If a woman with FAS drinks alcohol during pregnancy, she, too, may have a child with FAS. Not all individuals from alcohol-exposed pregnancies have obvious signs or symptoms of FAS. Individuals of different genetic backgrounds may be more or less susceptible to the damage that alcohol can cause. The dose of alcohol, the time during pregnancy at which the alcohol is used, and the pattern of alcohol use, all contribute to the different signs and symptoms that can be identified.

There is no racial or ethnic susceptibility to FAS. Individuals from different genetic backgrounds exposed to similar amounts of alcohol during pregnancy may exhibit different signs or symptoms of FAS. Several studies have estimated that between 25% and 45% of chronically alcoholic women will give birth to a child with FAS if they continue to drink during pregnancy. The risk of FAS appears to increase the older a chronically alcoholic woman becomes in her childbearing years and continues to drink. That is, a child with FAS will often be one of the last children born to a chronically alcoholic woman, although older siblings may exhibit milder features of FAS. Binge drinking, defined as the sporadic use of five or more standard alcoholic drinks per occasion, and moderate daily drinking (two to four 12 oz bottles of beer, 8 to 16 ounces of wine, 2 to 4 ounces of liquor) can also result in offspring with features of FAS.