Fetal Alcohol Syndrome
Alcohol has significant adverse effects on the developing embryo when mothers drink during pregnancy, and fetal alcohol exposure is the leading cause of mental retardation in the Western world. Originally described as fetal alcohol syndrome, this teratogenic syndrome is now recognized as part of a spectrum of detrimental effects due to alcohol, termed fetal alcohol spectrum disorder, which affects approximately 1% of live births in the United States. Fetal alcohol syndrome is diagnosed when the following are present: characteristic facial dysmorphology, growth restriction, and central nervous system/neurodevelopmental abnormalities. The effects on growth include prenatal growth deficiency, postnatal growth deficiency, and a low weight-to-height ratio. The characteristic facial features include short palpebral tissues between the upper and lower eyelids, maxillary hypoplasia (underdevelopment of the upper jaw), epicanthal folds from the nose to inner side of the eyebrow, a thin upper lip, and a flattened philtrum (the cleft from the nose to upper lip; Figure 6.7). Central nervous system anomalies include microcephaly (a smaller head compared with children of the same age and gender), developmental delays, intellectual disability, and neonatal problems. Fetal alcohol spectrum disorder describes a continuum of permanent birth defects caused by the maternal consumption of alcohol and refers to a complex pattern of behavioral or cognitive dysfunction, including learning difficulties, poor school performance, poor impulse control, problems relating to others, and deficits in language, abstract thinking, memory, attention, and judgment. Other disorders within this spectrum include alcohol-related neurodevelopmental disorders with only central nervous system abnormalities and alcohol-related birth defects with physical abnormalities (Box 6.7).
Factors such as the pattern and quantity of maternal drinking, stage of fetal development at the time of alcohol exposure, the use of other drugs, and sociobehavioral risk factors strongly influence the probability of developing fetal alcohol effects. The current recommendation of the Surgeon General of the United States is to drink no alcohol at all during pregnancy, because even small amounts of alcohol can lead to fetal alcohol spectrum disorder. According to the Institute of Medicine, 0.5 to 2.0 cases of fetal alcohol syndrome occur with every 1,000 live births in the United States. An epidemiological study conducted in 2000 found that the prevalence of fetal alcohol syndrome was 39.2 per 1,000 live births in the Western Cape Province of South Africa.
FETAL ALCOHOL SPECTRUM DISORDERSThis is an umbrella term that describes a range of effects that can occur in an individual whose mother drank alcohol during pregnancy. These effects may include physical, mental, behavioral, and/or learning disabilities with possible lifelong implications. The term FASD is not intended for use as a clinical diagnosis (for further reading, see Warren KR, Hewitt BG, Thomas JD. Fetal alcohol spectrum disorders: research challenges and opportunities. Alcohol Research and Health, 2011, 34: 4–14).
Fetal Alcohol SyndromeA diagnosis of full Fetal Alcohol Syndrome is made if the following three primary defining features are present:
- Documentation of characteristic facial abnormalities (smooth philtrum, thin vermillion border, and short palpebral fissures; see Figure 6.11)
- Documentation of prenatal and postnatal growth deficits
- Documentation of central nervous system abnormalities (i.e., structural, neurological, or behavioral, or a combination thereof).