Fetal Alcohol Syndrome



  • The four major features of classic fetal alcohol syndrome (FAS) are as follows:
    • CNS neurodevelopmental abnormalities
    • Facial dysmorphisms
    • Growth retardation
    • Maternal alcohol use during pregnancy
  • First described in 1973; classic FAS has since been recognized as one of the fetal alcohol spectrum disorders (FASDs), which include the following:
    • FAS, partial FAS (pFAS), alcohol-related neurodevelopmental disorder (ARND), and alcohol-related birth defects (ARBD)
    • Taken together, FASDs are 3 times more common than classic FAS, and the effects range from very mild symptoms to very severe.



  • Classic FAS: 0.5 to 2 per 1,000 live births
  • FASDs: 10 per 1,000 live births in the United States; 23 in 1,000 live births globally


  • Binge drinking historically has been noted to be the primary risk factor, although not all authors agree.
  • The highest prevalence of reported alcohol use during pregnancy is among those who are aged 35 to 44 years, African-American, college graduates, or employed.
  • Poor maternal nutrition appears to increase risk in the presence of maternal binge drinking.
  • Other risk factors include low educational attainment, history of multiple miscarriages and stillbirths, social isolation, history of physical or sexual abuse, and current interpersonal violence.
  • Maternal polymorphisms of the alcohol dehydrogenase gene (ADH): The presence of the ADH1B*3 allele appears to protect the fetus.
  • Concordance of FAS is higher in monozygotic than in dizygotic twins.


  • Women who are pregnant or may become pregnant should avoid alcohol. No “safe” level of alcohol consumption has been determined during pregnancy.
  • Women with alcohol addiction who are or may become pregnant should enter a treatment program.
  • According to the Centers for Disease Control and Prevention (CDC), 7.6% of pregnant women reported alcohol use during the month prior to being surveyed and 1.4% reported binge drinking.
  • The highest risk for FAS occurs in children whose mothers consume ≥4 drinks per occasion per week (peak blood alcohol level is more important than a lower sustained blood alcohol level).
  • In the United States, the Alcoholic Beverage Labeling Act passed in 1988 requires health warning labels, including risk of alcohol consumption during pregnancy.


  • Alcohol and its metabolite acetaldehyde are teratogens.
  • Alcohol causes malformation of the developing brain, as well as abnormal brain functioning in multiple regions of the brain.
  • Epigenetic changes caused by alcohol can disrupt normal gene expression.
  • Abnormalities can occur with alcohol consumption across all gestational ages.

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