A teratogen is any substance or influence that interferes with the normal development of a fetus and causes birth defects. Alcohol is the most commonly used teratogen in the United States. (The Merck Manual, 18th Edition. High-risk pregnancy: risk factors. 2006:2186-91)
Drinking alcohol during pregnancy can lead to a number of developmental deficits in a newborn; these defects are collectively known as fetal alcohol spectrum disorders (FASD).
The two most recognizable forms of FASD are fetal alcohol syndrome (FAS) and alcohol-related neurodevelopmental disorder.
Although FASD is more strongly associated with higher levels of alcohol consumption, animal studies suggest that even a single episode of drinking the equivalent of two alcoholic drinks during pregnancy can lead to destruction of fetal brain cells (one drink equals a 12-ounce beer, five ounces of wine, or 1.5 ounces of hard liquor). (Olney J. Fetal alcohol syndrome at the cellular level. Addict Biol 2004;9:137-49)
Unfortunately, a study of women of child-bearing age revealed that 10% used alcohol sometime during pregnancy, and 2% engaged in binge drinking (i.e., five or more drinks on one occasion). (National Task Force on Fetal Alcohol Syndrome and Fetal Alcohol Effect. Fetal alcohol syndrome: guidelines for referral and diagnosis.)
Clinical Features of Fetal Alcohol Syndrome
- Growth retardation, both prenatal and postnatal, resulting in a height or weight below the 10th percentile for age and race.
- Functional or structural central nervous system abnormalities leading to cognitive deficits and/or behavioral anomalies (attention-deficit/hyperactivity disorder, learning disabilities, etc.)
- Minor but distinctive facial anomalies: flattened nasal bridge and mid-face, upturned nose, epicanthal folds, smooth philtrum, laterally shortened eyes, thin upper lip, “railroad track” ears, abnormally small head, and drooping upper eyelids.
- Abnormally curved fingers and unusual (“hockey stick”) palmar creases.
Alcohol-related neurodevelopmental disorder is characterized by the alcohol-induced occurrence of central nervous system abnormalities without the typical facial features of FAS.
Risk Factors for Fetal Alcohol Syndrome
- FAS is not hereditary. A woman affected by FAS cannot pass the syndrome to her children unless, she, too, uses alcohol during pregnancy.
- Maternal age over 30 increases the risk for FASD.
- Low socioeconomic status increases risk.
- Binge drinking raises the risk relatively higher than consuming smaller amounts of alcohol.
Treatment for Fetal Alcohol Syndrome
Management of individuals affected by FASD requires a multidisciplinary approach involving medical professionals (early diagnosis and intervention improves long-term function), social services (to ensure a safe home environment and educate parents), school services (to provide optimal educational opportunities), and disability services (a diagnosis of FAS may allow children to qualify for assistance via the Individuals with Disabilities Education Act).
Prevention of Fetal Alcohol Syndrome
- Alcohol damages fetal brain cells by a direct toxic effect.
- No period during pregnancy has been shown to be safe from the damaging effects of alcohol.
- Damage to the fetal nervous system can result from alcohol exposure in any trimester, even before a pregnancy test becomes positive.
- Women who are pregnant—or those who are attempting to become pregnant—should avoid alcohol consumption from the time of conception until birth.
(From Wattendorf D, Muenke M. Fetal alcohol spectrum disorders. Am Fam Phys. 2005;72(2):279-82)
Fetal alcohol spectrum disorders, whose consequences are lifelong and significant, are completely preventable. No amount of alcohol during pregnancy is known to be risk-free, and no prenatal period is safe. Women should avoid all alcohol consumption during pregnancy.
