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Fetal Alcohol Syndrome

In 1973, the medical journal, Lancet, published the findings of researchers K.L. Jones and D.W. Smith: Recognition of the Fetal Alcohol Syndrome in Early Infancy. This article coined the term "fetal alcohol syndrome" (FAS) to describe a pattern of abnormalities observed in children born to alcoholic mothers.

Early researchers postulated that malnutrition might be responsible for these defects. However, the pattern of malformation associated with FAS is not seen in children born to malnourished women, and alcohol has been found to be acutely toxic to the fetus independently of the effects of malnutrition.

Criteria for defining FAS are:

  1. Prenatal and/or postnatal growth retardation (weight and /or length below the 10th percentile)

  2. Central nervous system involvement, including neurological abnormalities, developmental delays, behavioral dysfunction, intellectual impairment, and skull or brain malformations

  3. A characteristic face with short palpebral fissures (eye openings), a thin upper lip, and an elongated, flattened midface and philtrum (the groove in the middle of the upper lip)

Mental handicaps and hyperactivity are probably the most debilitating aspects of FAS, and prenatal alcohol exposure is one of the leading known causes of mental retardation in the Western World. Problems with learning, attention, memory, and problem solving are common, along with incoordination, impulsiveness, and speech and hearing impairment. Deficits in learning skills persist even into adolescence and adulthood.

Range of Adverse Effects
It is generally accepted that the adverse effects of prenatal alcohol exposure exist along a continuum, with the complete FAS syndrome at one end of the spectrum and incomplete features of FAS, including more subtle cognitive-behavioral deficits, on the other. Thus, infants with suboptimal neurobehavioral responses may later exhibit subtle deficits in such aspects of daily life as judgment, problem solving,
and memory.

Incidence and Demographics
According to a Center for Disease Control (CDC) study, incidences of FAS per 1,000 total births for different ethnic groups in the United States were as follows:
  • Asians 0.3
  • Hispanics 0.8
  • whites 0.9
  • blacks 6.0
Several factors, such as cultural influences, patterns of alcohol consumption, nutrition, and metabolic differences have been suggested to play a role in this difference.

How Much Alcohol is too Much?
Apart from epidemiology, the key questions in FAS research include, How much alcohol is too much? and, When is the fetus at greatest risk? The major problem in addressing these questions is the lack of a specific physiological measure that accurately reflects alcohol consumption. There is no biological marker currently available to measure alcohol intake, and self-reports of alcohol consumption may be unreliable , perhaps especially so during pregnancy.

Given the range of defects that result from prenatal alcohol exposure, the search for an overall threshold for fetal risk may be unreasonable. Instead, each abnormal outcome in brain structure and function and growth might have its own dose-response relationship. Thus, heavy alcohol consumption throughout pregnancy results in a wide variety of effects characteristic of FAS, while episodic binge drinking at high levels results in partial expression of the syndrome, with the abnormalities being unique to the period of exposure. Vulnerability of individual organ systems may be greatest at the time of their most rapid cell division.

Underreporting of Alcohol Use in Pregnancy
Findings reported by M. Morrow-Tlucak et al. in "Alcoholism: Clinical and Experimental Research" [13(3):399-401, 1989], Underreporting of alcohol use in pregnancy: Relationship to alcohol problem history, suggest that women with more serious alcohol-related problems are those more likely to underreport their alcohol consumption when interviewed during pregnancy.

While it is apparent that children who meet the criteria for FAS are born only to those mothers who consume large amounts of alcohol during pregnancy, studies have reported neurobehavioral deficits and intrauterine growth retardation in infants born to mothers who reported themselves to be moderate alcohol consumers during pregnancy.

Enoch Gordis, M.D., Director, National Institute on Alcohol Abuse and Alcoholism, offers this commentary on alcohol use during pregnancy:

"From a scientific perspective, the link between moderate drinking and alcohol-related birth defects has not been clearly established.
Whether there is a threshold below which alcohol can be consumed without harming the fetus is not known: self-reported data showing a relationship between moderate use and alcohol-related birth defects may often underestimate the true level
of drinking.

Clinicians, however, must offer advice to their patients based upon the best available scientific evidence. Although some clinicians believe that recommending total abstention for pregnant women may subject them to unwarranted guilt about drinking small amounts of alcohol, most accept the need for clinical caution. Because we do not know at what point alcohol damage begins, it is prudent to recommend, as I do, that pregnant women abstain from alcohol use pending confirmation of alcohol's role vis-a-vis
fetal development."

More Resources

Some of the information on this page has been excerpted and adapted from material prepared by the National Institute on Alcoholism and
Alcohol Abuse.