Fetal Alcohol Syndrome

Basics

Description

  • 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 three times more common than classic FAS, and the effects range from very mild symptoms to very severe.

Epidemiology

Incidence

  • Classic FAS: 3.1 per 1,000 live births
  • FASDs: 9.1 per 1,000 live births

Risk Factors

  • Binge drinking seems to be the primary risk factor.
  • The highest prevalence of reported alcohol use during pregnancy are among those who are aged 35–44 years, white, college graduates, or employed.
  • Poor maternal nutrition appears to increase risk in the presence of maternal binge drinking.
  • 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.

General Prevention

  • 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, Alcoholic Beverage Labeling Act passed in 1998 requires heath warning labels, including risk of alcohol consumption during pregnancy.

Pathophysiology

  • Malformation of the developing brain is the primary pathophysiologic event resulting in secondary neurodevelopmental pathology and facial dysmorphisms in classic FAS.
  • May involve increased susceptibility to cell damage by free radicals in the developing fetus, especially in the first trimester
  • Alcohol and its metabolite acetaldehyde are teratogens.

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