Fetal Alcohol Spectrum Disorder

Fetal alcohol spectrum disorder (FASD) is a group of neonatal pediatric disorders caused by maternal alcohol consumption during pregnancy. The term entails a range of physical and neurodevelopmental effects. Classification is based on severity and clinical presentation. Diagnosis is based on a history of prenatal alcohol exposure and the presence of characteristic physical and developmental abnormalities. Management involves surgical correction of structural anomalies and early initiation of support services to promote best outcomes.

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Overview

Definition

Fetal alcohol spectrum disorder (FASD) Consists of the postnatal physical, developmental, cognitive, and psychiatric deficits noted in a patient who has been exposed to alcohol while in utero.

Epidemiology

  • Prevalence:
    • 1.5% of live births in the United States
    • 0.77% of live births globally:
      • Highest prevalence in WHO European region
      • Lowest prevalence in WHO Eastern Mediterranean region
  • Most common cause of teratogenic intellectual disability
  • Leading preventable cause of intellectual disability in the United States
  • Seen commonly in children who:
    • Are in the foster care system
    • Are in psychiatric care facilities
    • Have been placed in child protective services or the juvenile justice system
  • Maternal risk factors include:
    • Older maternal age
    • Having a previous child with FASD
    • History of poor prenatal care
    • History of social isolation
    • History of substance abuse

Etiology

  • Only known cause is intrauterine alcohol exposure.
  • Increased risk of developing FASD with:
    • High-dose exposure (blood alcohol content (BAC) > 150 mg/dL)
    • Chronic alcohol ingestion
    • Binge drinking
  • Prevalence increases in parallel with the increase in amount of alcohol consumed during pregnancy.

Classification

Being an umbrella term, FASD has multiple conditions nested within it:

  • Fetal alcohol syndrome (FAS)
  • Partial fetal alcohol syndrome (pFAS)
  • Alcohol-related neurodevelopmental disorder (ARND)
  • Neurobehavioral disorder associated with prenatal alcohol exposure (ND-PAE)
  • Alcohol-related birth defects (ARBD)

Pathophysiology

Alcohol is a teratogen that has irreversible effects:

  • Exact mechanism unknown
  • Teratogenic effects can occur during any stage of pregnancy.
  • No safe level of alcohol consumption during pregnancy

Factors that contribute to pathogenesis:

  • Ethanol and its metabolites transfer across placenta.
  • Fetus cannot metabolize alcohol: depends on maternal alcohol dehydrogenase for hepatic detoxification
  • Amniotic fluid acts as reservoir for alcohol (prolongs fetal exposure).
  • Ethanol directly affects fetus’s developing CNS by interfering with:
    • Cell proliferation and differentiation
    • Neuronal and glial cell migration

Variation in susceptibility of fetus affected by:

  • Pattern of alcohol ingestion:
    • Increased risk with high-dose exposure of BAC > 150 mg/dL
    • Increased risk with binge drinking
  • Maternal and fetal genetics
  • Maternal nutritional status
  • Maternal age
  • Other concurrent teratogenic exposures

Clinical Presentation

Various combinations of features can be present.

  • Characteristic craniofacial features:
    • Short palpebral fissures
    • Midface hypoplasia with long, smooth philtrum
    • Thin upper lip
    • Epicanthal folds
    • Decreased interpupillary distance
  • Growth retardation:
    • < 10th percentile for weight and/or height
    • Prenatal
    • Postnatal
  • CNS: structural
    • Microcephaly
    • Absent corpus callosum
  • Neurologic:
    • Abnormal reflexes
    • Abnormal tone
    • Seizures
  • Functional:
    • Intellectual disability
    • Speech delays
    • Difficulty with executive function
    • Memory problems
    • Abnormal motor function
    • Poor impulse control
    • Hyperactivity and concentration deficits
    • Poor social skills and adaptive functions
  • Cardiovascular:
    • Ventricular septal defect (VSD)
    • Patent ductus arteriosus (PDA)
    • Atrial septal defect (ASD)
    • Tetralogy of Fallot
    • Heart-lung fistulas
  • Musculoskeletal:
    • Hockey stick palmar creases
    • Limb dislocation
    • Pectus excavatum and carinatum
    • Hemivertebrae
    • 5th finger clinodactyly
  • Ophthalmologic:
    • Strabismus
    • Ptosis
    • Optic nerve hypoplasia
  • Genitourinary:
    • Aplastic, dysplastic, or hypoplastic kidney
    • Horseshoe kidney
  • Auditory:
    • Conductive hearing loss
    • Sensorineural hearing loss
Male baby with FAS syndrome

Fetal alcohol spectrum disorder: infant with characteristic facial features

Image: “Male baby with FAS syndrome” by Teresa Kellerman. License: CC BY-SA 3.0

Diagnosis

Accurate and early diagnosis of FASD at < 6 years of age is important to enable interventions and improve outcomes.

  • Diagnostic evaluation by interdisciplinary team is needed, including:
    • Developmental pediatrics
    • Neurology
    • Neuropsychology
    • Genetics
    • Occupational therapy
  • Various sets of diagnostic criteria, including:
    • Growth retardation
    • Facial dysmorphism
    • CNS abnormalities
    • Structural birth defects
    • Prenatal alcohol exposure:
      • Quantity
      • Frequency
      • Timing during pregnancy

Management

There is currently no treatment for FASD; management focuses on early intervention and prevention.

  • Correction of surgically amenable congenital defects
  • Parent training to meet increased medical and developmental needs of child
  • Early interventional therapies (birth to age 3):
    • Occupational therapy
    • Physical therapy
    • Speech therapy
  • Behavioral interventions to develop:
    • Executive function
    • Social skills
    • Adaptive skills
  • Educational support services:
    • Academic skills
    • Vocational training
  • Psychotropic medications for:
    • ADHD
    • Anxiety
    • Mood dysregulation

Prognosis and prevention

  • Lack of diagnosis and management increases risk for:
    • Adverse childhood events
    • Poor school performance
    • Trouble with law enforcement/incarceration
    • Inappropriate sexual behavior
    • Unemployment
    • Substance abuse
    • Mental health disorders
    • Premature death
  • Prevention:
    • Education about effects of alcohol on fetus
    • Promotion of alcohol abstinence
    • Screening to identify high-risk pregnant women

Differential Diagnosis

  • ADHD: neurodevelopmental disorder characterized by a pattern of inattention and/or hyperactivity/impulsivity that occurs in ≥ 2 different settings for more than 6 months. The clinical presentation of ADHD varies in severity. Diagnosis is made on the basis of neuropsychological assessment. Management includes education, behavioral modification, educational support services, and pharmacologic therapy.
  • Fragile X syndrome: most common genetic cause of intellectual disability. Fragile X syndrome is caused by an X-linked mutation in the FMR1 gene and is diagnosed by DNA analysis. Clinical presentation includes characteristic physical features of long, narrow facies, large ears, and macroorchidism. Cognitive impairment, abnormal behavior, and seizures are also features. Management includes developmental, behavioral, and educational interventions. Medication may be used for cognitive and behavioral aspects.
  • Williams syndrome: autosomal dominant genetic disorder caused by microdeletions on chromosome 7. The clinical presentation of Williams syndrome includes characteristic facial features such as short palpebral fissures, long philtrum, and epicanthal folds. Cardiovascular, neurodevelopmental, renal, endocrine, and growth abnormalities are also present. Diagnosis is made by genetic testing. Management involves addressing cardiovascular anomalies and providing interventions for neurodevelopmental issues.

References

  1. National Organization on Fetal Alcohol Syndrome. Retrieved April 10, 2021, from www.nofas.org/about-fasd/
  2. American Academy of Pediatrics Fetal Alcohol Spectrum Disorders Toolkit. Common definition. Retrieved April 10, 2021, from http://www.aap.org/en-us/advocacy-and-policy/aap-health-initiatives/fetal-alcohol-spectrum-disorders-toolkit/Pages/Common-Definitions.aspx 
  3. Riley EP, Infante MA, Warren KR. (2011). Fetal alcohol spectrum disorders: an overview. Neuropsychol Rev. https://pubmed.ncbi.nlm.nih.gov/21499711/ 
  4. Sokol RJ, Delaney-Black V, Nordstrom B. (2003). Fetal alcohol spectrum disorder. JAMA. https://pubmed.ncbi.nlm.nih.gov/14665662/ 
  5. Weitzman C, Rojmahamangkol P. (2020). Fetal alcohol spectrum disorder: management and prognosis. UpToDate. Retrieved April 9, 2021, from https://www.uptodate.com/contents/fetal-alcohol-spectrum-disorder-management-and-prognosis
  6. Centers for Disease Control. (2020). Fetal alcohol spectrum disorders. https://www.cdc.gov/ncbddd/fasd/facts.html
  7. Waz W, Lee T. (2020). Williams syndrome. UpToDate. Retrieved April 10, 2021, from https://www.uptodate.com/contents/williams-syndrome
  8. Centers for Disease Control. (2020). Fragile X syndrome. https://www.cdc.gov/ncbddd/fxs/facts.html

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