Fetal Alcohol Syndrome (FAS)

Syndrome characterized by a series of physical, mental, and neurobehavioral birth defects resulting from chronic alcohol consumption during pregnancy.

(Figure)

Alcohol Antenatal Exposition; Alcoholic Embryopathy.

First described in France by J. Lemoine in 1968 and in the United States by Jones and Smith in 1973. The literature is prominent because FAS is considered the leading known cause of mental retardation affecting all socioeconomic groups and races.

Between 0.5 and 5 per 1000 live births, making fetal FAS the leading cause of mental retardation and birth defects. More frequent in infants born to black mothers, especially those with ADH2-1/3 phenotype (an unusual phenotype in white women). The incidence among children born to heavy drinkers is 4%.

Not a genetic condition; rather it is a toxic syndrome. However, women with the alcohol dehydrogenase 2 genotype 1/3 (ADH2-1/3) seem to be at greater risk for having an affected infant, but this may be the result of greater ingestion of alcohol.

Unknown, but the teratogenic effect of alcohol on the fetus is suspected to result from the formation of free radicals causing cellular damage on the developing tissues of the fetus. Exposure early in pregnancy is responsible for the defective organogenesis and abnormal craniofacial development, whereas continuing alcohol exposure throughout pregnancy causes growth deficiency. Neurodevelopmental effects caused by alcohol are present during the three trimesters because the brain undergoes development at all stages of pregnancy.

Diagnosis is clinical based on the physical findings in the infant and the history of alcohol consumption during early pregnancy. Diagnosis criteria have been established by the Institute of Medicine and the National Academy of Sciences.

FAS is an ensemble of findings found in children exposed to alcohol in utero. They include prenatal and postnatal growth deficiency, short palpebral fissures, ptosis, flat midface, upturned nose, smooth philtrum with thin upper lip, microcephaly, learning disabilities associated with mild-to-moderate mental retardation, fine motor dysfunction, hyperactivity, ventriculoseptal defect, atrial septal defect, and minor musculoskeletal findings.

Clinically suspected cardiac defects should be ruled out with an echocardiogram.

Cooperation may be absent in some children with behavioral dysfunction, so premedication is advisable. Rarely patients have micrognathia and/or a short, webbed neck that may make direct laryngoscopy and tracheal intubation more difficult.

In the presence of a cardiac defect, antibioprophylaxis may be required.