Physician: Education: Descriptions of Disorders

In the United States, fetal alcohol syndrome (FAS) is thought to affect 1 in 500 children. FAS is the most common cause of mental retardation, surpassing even Down syndrome (approximately 1 in 700 births). Children who show some milder effects of prenatal alcohol exposure but do not have the full fetal alcohol syndrome are said to have fetal alcohol effects (FAE). If those with fetal alcohol effects are included, the frequency of children adversely affected by prenatal alcohol exposure may be as high as 1 in 300.

There is a wide range of severity in FAS/FAE; some individuals will have only one or two features, while others may show many severe symptoms. Exposure to alcohol before birth has important effects in three main areas: intelligence and behavior, growth and development, and physical features. Over 75% of children with fetal alcohol syndrome have mild to moderate mental retardation with average I.Q. in the 60's (average I.Q. for unaffected individuals is 100). The brain and head in this condition are typically small (a condition called microcephaly). Babies show behaviors which include irritability, and poor sucking and swallowing. They may be unusually jittery and show a dramatic and exaggerated response to noise. They may be "floppy" with decreased muscle tone, or "tight" with stiff, tense muscles. Older children are often hyperactive, with learning disabilities and poor attention spans. Other behavior problems include impulsivity, sleep disorders, and difficulty in making and maintaining friendships. Approximately 10-20% have a seizure disorder. Prenatal alcohol exposure can damage the nerves for vision and hearing, leading to decreased vision and hearing loss. The second major manifestation is an affect on growth. These children are significantly smaller than average, both at birth and afterwards. This effect is seen in both length and weight. As noted above, the head is also considerably smaller than normal. There are several facial features which are typical in those individuals with FAS. The most common are narrow palpebral fissures (the lengthwise area of the eye that you see between the upper and lower eyelid), a short upturned nose, thin upper lip, and a smooth appearance to the lengthwise area between upper lip and nose (philtrum). This last feature is due to an underdevelopment of the philtrum, or ridges which normally form in this area. Less common facial features include "droopy"eyelids and a cleft lip and/or cleft palate. Alcohol also affects the development of other areas of the body. Heart murmurs caused by a hole in the atrial septum (ASD) or ventricular septum (VSD) are often seen, and there are occasionally more severe heart defects. The fingers may be shortened, and have underdeveloped nails (especially the nail of the fifth digit). There may be joint abnormalities, malformations of the vertebrae (bones of the spine), and underdeveloped kidneys.

Fetal alcohol syndrome is caused by exposure of the developing fetus to alcohol, and is not inherited.

Alcohol is a teratogen (substance that increases the incidence of birth defects). The effect of alcohol exposure will depend somewhat on the time in gestation when exposure occurred, as well as the amount and frequency of alcohol intake. The organs of an embryo or fetus grow and develop at different times during pregnancy, so exposure in the third week may have very different results than exposure in the 23rd week. In general, the first two weeks of pregnancy are considered an "all or none" period. Significant alcohol exposure at this time is more likely to cause pregnancy loss (miscarriage) than a birth defect. The next six weeks (the "embryonic period") is a very critical period when organs such as the brain, heart, eyes, ears, kidneys and the genitals form. This is the most worrisome time for alcohol exposure, as it may cause malformation of these structures. Later exposure can still have a significant effect, but is more likely to cause a problem with growth or function, since formation has already occurred. For example, if a woman drinks heavily in the 3rd to 6th week of pregnancy (the most important time for formation of the brain), the fetus may have a defect in the brain's structure - such as an abnormal shape, or portions which have not formed at all. If a woman drinks heavily only in the later stages of pregnancy, the brain would be structurally normal, but may be small. Because development of the brain and nervous system is so complex, even damage late in the pregnancy can lead to functional problems, such as learning disabilities and behavior disorders.

There is no diagnostic test for fetal alcohol syndrome/fetal alcohol effects. The diagnosis depends on a history of prenatal exposure to alcohol, mental retardation/behavioral difficulties, and suggestive physical features.

Once damage from prenatal exposure to alcohol has been done, it cannot be reversed. However, these children can be helped tremendously by early recognition of the disorder. In this way, intervention with physical or intellectual therapies can begin as early as possible, and any medical needs (such as a heart condition or cleft palate) can be addressed.

The incidence of FAS/FAE is known to be particularly high in Native Americans.

National Organization on Fetal Alcohol Syndrome
Fetal Alcohol Syndrome Family Resource Institute

Gorlin RJ, Cohen MM Jr, Levin LS (eds).
Syndromes of the Head and Neck (3rd ed).
Oxford University Press, New York. p 15-20, 1990 .

Johnson VP, Swayze W II, Sato Y, Andersen NC.
Fetal alcohol syndrome: Craniofacial and central nervous system manifestations.
Am J Med Genet 61:329-339, 1996. abstract

Lewis DD, Woods SE.
Fetal alcohol syndrome.
Am Fam Phys 50(5):1025-1032, 1994. abstract

Committee on Substance Abuse and Committee on Chil.
Recommendations on fetal alcohol syndrome and alcohol-related neurodevelopmental disorders.
Pediatrics 2000;106(2):358. abstract

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