Fetal alcohol syndrome

Dylan Todd MD (Dr. Todd of the University of Iowa has no relevant financial relationships to disclose.)
Daniel J Bonthius MD PhD (Dr. Bonthius of the University of Iowa has no relevant financial relationships to disclose.)
Bernard Maria MD, editor. (Dr. Maria of Icahn School of Medicine at Mount Sinai and Director of Pediatric Neurology and Developmental Medicine at Goryeb Children)
Originally released November 5, 1998; last updated January 19, 2017; expires January 19, 2020

This article includes discussion of fetal alcohol syndrome, fetal alcohol effects, alcohol-related birth defects, and alcohol-related neurodevelopmental disorders. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.

Overview

Fetal alcohol syndrome is the most common preventable cause of intellectual disability in the Western world. In addition to inducing developmental delay, gestational alcohol exposure can lead to a variety of neurodevelopmental abnormalities, including epilepsy, attention deficit hyperactivity disorder, and academic difficulties. Many of these behavioral deficits in children with fetal alcohol syndrome are due to alcohol-induced neuronal death. In this updated article, the authors discuss the mechanisms by which alcohol damages the developing brain and potential protective agents. In addition, the authors discuss the role of genetics in determining vulnerability to alcohol-induced brain injury.

Key points

 

• Fetal alcohol syndrome is the constellation of developmental defects that results from maternal alcohol abuse during pregnancy.

 

• Although the syndrome includes prenatal and postnatal growth disturbances and abnormalities of midface development, brain dysfunction is the most clinically important component of the syndrome.

 

• Impairments in learning and attention constitute the most common neurologic problems of fetal alcohol syndrome.

 

• Neuronal death plays a central role in the pathogenesis and outcome of fetal alcohol syndrome.

Historical note and terminology

It has been known for centuries that the children of alcoholic women are often intellectually impaired. In Problemata (322 BCE), Aristotle observed that “foolish, drunken or hare-brained women for the most part bring forth children like unto themselves, difficult and listless.” The Babylonian Talmud (200 CE to 500 CE) warns that “one who drinks intoxicating liquor will have ungainly children.”

Through most of history, alcoholism has been seen not as a medical problem but as a moral failure. It was assumed that the flawed children of alcoholic women acquired their defects, not from alcohol, but from the constitutional weaknesses of their mothers. Only recently has it been recognized that the fetus is directly and adversely affected by alcohol and that the ill effects are similar enough from one affected child to the next to constitute an identifiable syndrome.

In 1968, an article by Lemoine and coworkers was published in a French medical journal describing a combination of physical defects and neuropsychological abnormalities affecting the children of alcoholic mothers (Lemoine et al 1968). The reported physical defects included abnormal facies, heart anomalies, and limb deformities. The neuropsychological manifestations included delayed psychomotor and language development and lowered intelligence quotient. The article received little attention. During the subsequent 5 years, few follow-up clinical or experimental studies were published examining the possibility of alcohol-induced birth defects.

In 1973, unaware of Lemoine's report, Smith and coworkers at the University of Washington described a constellation of developmental defects attributed to maternal alcohol abuse during pregnancy (Jones and Smith 1973; Jones et al 1973). The constellation, which closely resembled the signs described by Lemoine, included facial abnormalities, pre- and postnatal growth deficiencies, defects in major organ systems, limb anomalies, microcephaly, and developmental delay. The authors named this constellation of developmental defects the “fetal alcohol syndrome,” and their work received immediate international attention. Since 1973, hundreds of clinical and experimental studies have been published exploring the effect of alcohol on fetal development.

Today, fetal alcohol syndrome is defined by a triad of developmental abnormalities that include the following: (1) prenatal and postnatal growth retardation, (2) a characteristic set of midface abnormalities, and (3) central nervous system dysfunction. All 3 components must be present to make the diagnosis of fetal alcohol syndrome.

Within several years of the original description of fetal alcohol syndrome, it was discovered that not all of the characteristic features of the syndrome are always expressed following intrauterine alcohol exposure. Children whose mothers abused alcohol during pregnancy and who exhibit some, but not all, of the clinical signs of fetal alcohol syndrome are classified as having alcohol-related birth defects, fetal alcohol effects, or alcohol-related neurodevelopmental disorders (Stratton et al 1996; Hoyme et al 2005).

Because of this recognition that alcohol can produce a variety of permutations and combinations of adverse fetal effects, the term “fetal alcohol spectrum disorder” has been coined to cover the range of outcomes associated with all levels of prenatal alcohol exposure (Sokol et al 2003). Educators, advocates, and federal agencies (including the National Institute on Alcohol Abuse and Alcoholism and the Centers for Disease Control and Prevention) have adopted “fetal alcohol spectrum disorder” as an umbrella term to promote a better understanding and description of alcohol's wide-ranging teratogenic effects. Unlike “fetal alcohol syndrome,” which is a defined syndrome whose features are clearly linked to alcohol, fetal alcohol spectrum disorder does not have defined features. Instead, fetal alcohol spectrum disorder is a term used to describe an adverse outcome suspected, but not necessarily proven, to have been due to prenatal alcohol exposure.

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