CHAPTER 147

Fetal Alcohol Syndrome

Melissa K. Egge, MD, FAAP

Fetal alcohol spectrum disorder (FASD) encompasses the spectrum of clinical findings caused by prenatal alcohol exposure. The 4 subcategories of FASD are fetal alcohol syndrome (FAS), partial FAS, alcohol-related neurodevelopmental disorder, and alcohol-related birth defects. A diagnosis of partial FAS requires facial dysmorphism in addition to growth disturbances or central nervous system (CNS) abnormalities. Alcohol-related neurodevelopmental disorder involves the functional impairments associated with prenatal alcohol exposure; however, clear diagnostic criteria are still being developed. Alcohol-related birth defects include structural birth defects that are associated with, but are not specific for, prenatal alcohol exposure (Box 147.1). This chapter will focus on FAS.

Fetal alcohol syndrome is a clinical diagnosis necessitating careful evaluation by an experienced physician to recognize the physical, behavioral, and cognitive abnormalities in an affected child. Diagnosis may be made at birth, but often the condition is not diagnosed until school age. Fetal alcohol syndrome has been recognized in the medical literature for decades and in historical literature for centuries; however, refining the criteria for diagnosis has been an ongoing process. Several entities have created guidelines to help analyze children with FAS, but in 2004, the Centers for Disease Control and Prevention (CDC) published broad-based criteria that are helpful for several reasons (Box 147.2). First, they educate physicians and caregivers about the wide spectrum of phenotypes that manifest after prenatal alcohol exposure. Second, they use the most recent CDC criteria for FAS, which helps capture the greatest number of potentially affected children with the goal of providing earlier intervention with a wider scope of services. Criteria must be met in all 3 categories of facial features, growth problems, and CNS abnormalities. For the patient with suspected FAS but for whom diagnostic criteria are incompletely met, the term FASD may be used to couch the findings, especially in the setting of confirmed maternal alcohol exposure. In the future, diagnostic criteria may be developed for other subcategories of FASD. Currently, however, the term FASD is not intended for diagnostic purposes but rather a descriptor of recognized phenotypes along a spectrum leading up to FAS.

Part of the difficulty in delineating a phenotype for alcohol exposure is that the degree of exposure is variable during embryogenesis (and organogenesis); factors include quantity ingested, concomitant drug exposures, malnutrition, and individual genetic responses to exposure. This wide variability in degree of exposure and individual response results in a multitude of clinical presentations.

Epidemiology

Prenatal alcohol exposure is much more common than the number of diagnosed cases of FAS would suggest. It has been estimated in surveys of women of childbearing age in the United States during 2011-2013 that approximately one-half of nonpregnant women of childbearing age reported some alcohol consumption and approximately 18% reported binge drinking (>4 drinks on 1 occasion) in the past 30 days. Among pregnant women, approximately 1 in 10 reported any alcohol use and 3% reported binge drinking in the past 30 days. Although estimates of children affected by FAS vary by region and population, an estimated 1 in 1,000 live births would meet criteria for diagnosis.

The estimate jumps 10-fold when certain high-risk groups are the focus. Approximately 1 in 100 children in foster care and nearly that many Native American children (3–9 per 1,000) meet criteria for diagnosis of FAS. Inclusion of children who meet some but not all criteria for FAS results in a prevalence of 1% to 5% or higher in high-risk populations.

Pathophysiology

Alcohol is a teratogen, and like other teratogens its effect on the developing fetus depends on several factors, many of which are difficult to record. Although it is important to ask about the timing, quantity, and pattern of prenatal alcohol exposure, it is often difficult to obtain an accurate history. Additionally, because of genetic differences in women’s ability to metabolize ethanol by alcohol dehydrogenase, each fetus receives a unique “dose” during gestation. Also individualized is each woman’s nutritional intake and use of other drugs or medications. Alcohol acts as a toxin to cause damage and apoptosis to neurons in the fetal brain. Alcohol also inhibits proper migration, development, and functioning of cells during embryogenesis, contributing to structural anomalies in multiple organ systems, such as the kidney, heart, and brain.

Clinical Presentation

Signs and symptoms of FAS may be recognized at birth or not until later in childhood. At birth, a neonate may present with asymmetric intrauterine growth restriction, small for gestational age, head circumference disproportionately smaller than the body, or appropriate for gestational age. A variety of birth defects have been associated with fetal alcohol exposure, and many of these have been demonstrated in animal models. A newborn may exhibit signs of withdrawal from alcohol or concomitant drug exposure. With time, the infant may demonstrate failure to thrive or poor weight gain resulting from poor nursing. Infants exposed to alcohol in utero also present with nonspecific symptoms of irritability and dysregulated sleep patterns. In toddlerhood, developmental delays may be recognized by a caregiver or during developmental screening questions by a primary care physician. As a child approaches school age, a teacher may report behavioral concerns and poor school performance. Concerns such as distractibility, hyperactivity, and difficulty processing multistep directions may be raised in school. Additionally, a child may exhibit signs of fine motor delay, such as difficulty tying shoes or fastening buttons. Deficits in visual-spatial and math concepts are common for children with fetal alcohol exposure. Age-appropriate social skills are lacking in affected children, who often do not develop street smarts. They take the blame, succumb to peer pressure, and are oblivious to social norms. Approaching the teenage years, the classic facies may become less distinctive. As teenagers mature, their cognitive and behavioral weaknesses predispose them to mental health issues, such as depression, anxiety, and problems with substance abuse.

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