The hippocampus plays a role in memory, learning, emotion, and encoding visual and auditory information, all of which can create neurological and functional central nervous system (CNS) impairments as well.
How Alcohol Affects the Fetus
The placenta allows free entry of ethanol and toxic metabolites like acetaldehyde into the fetal compartment. The so-called placental barrier is no barrier with respect to ethanol.
The developing fetal nervous system appears particularly sensitive to ethanol toxicity. The latter impacts negatively on proliferation, differentiation, neuronal migration, axonic outgrowth, integration and fine tuning of the synaptic network. In short, all major processes in the developing central nervous system appear compromised.
Fetal tissues are quite different from adult tissues in function and purpose. For example, the main detoxicating organ in adults is the liver, whereas fetal liver is incapable of detoxicating ethanol as the ADH and ALDH enzymes have not yet been brought to expression at this early stage.
Up to term, fetal tissues do not have significant capacity for the detoxification of ethanol, and the fetus remains exposed to ethanol in the amniotic fluid for periods far longer than the decay time of ethanol in the maternal circulation.
Generally, fetal tissues have far less antioxidant protection than adult tissues as they express no significant quantities of ADH or ALDH, and far less antioxidant enzymes like SOD, glutathione transferases or glutathione peroxidases.
- Fetal Alcohol Syndrome (FAS), the most severe condition, refers to individuals who have a specific set of birth defects and neurodevelopmental disorders characteristic of the diagnosis.
- Partial Fetal Alcohol Syndrome (pFAS) refers to individuals with a known, or highly suspected history of prenatal alcohol exposure who have alcohol-related physical and neurodevelopmental deficits that don’t meet the full criteria for FAS.
- Alcohol-Related Neurodevelopmental Disorder (ARND) a subtype of pFAS
- Alcohol-Related Birth Defects (ARBD) also a subtype of pFAS
In addition to FAS, pFAS, ARND, and ARBD, any other conditions believed to be related to prenatal alcohol exposure, such as spontaneous abortion and sudden infant death syndrome (SIDS), are also considered to be on the spectrum of related disorders.
While functional abnormalities are the behavioral and cognitive expressions of the FASD disability, CNS damage can be assessed in three areas: structural, neurological, and functional impairments.
Problems may include an abnormal appearance, short height, low body weight, small head size, poor coordination, low intelligence, behavior problems, and problems with hearing or seeing.
Functional impairments are deficits, problems, delays, or abnormalities due to prenatal alcohol exposure (rather than hereditary causes or postnatal insults) in observable and measurable domains related to daily functioning, often referred to as developmental disabilities.
Those affected are more likely to have trouble in school, legal problems, participate in high-risk behaviors, and have trouble with alcohol or other drugs.
The primary disabilities of FAS are the functional difficulties with which the child is born as a result of CNS damage due to prenatal alcohol exposure.
Often, primary disabilities are mistaken as behavior problems, but the underlying CNS damage is the originating source of a functional difficulty, rather than a mental health condition, which is considered a secondary disability.
Learning impairments are associated with impaired dendrites of the hippocampus. Impaired motor development and functioning are associated with reduced size of the cerebellum. Hyperactivity is associated with decreased size of the corpus callosum.
Functional difficulties may result from CNS damage in more than one domain, but common functional difficulties by domain include:
- Achievement: Learning disabilities
- Adaptive behavior: Poor impulse control, poor personal boundaries, poor anger management, stubbornness, intrusive behavior, too friendly with strangers, poor daily living skills, developmental delays
- Attention: Attention-Deficit/Hyperactivity Disorder (ADHD), poor attention or concentration, distractible
- Cognition: Intellectual disability, confusion under pressure, poor abstract skills, difficulty distinguishing between fantasy and reality, slower cognitive processing
- Executive functioning: Poor judgment, Information-processing disorder, poor at perceiving patterns, poor cause and effect reasoning, inconsistent at linking words to actions, poor generalization ability
- Language: Expressive or receptive language disorders, grasp parts but not whole concepts, lack understanding of metaphor, idioms, or sarcasm
- Memory: Poor short-term memory, inconsistent memory and knowledge base
- Motor skills: Poor handwriting, poor fine motor skills, poor gross motor skills, delayed motor skill development (e.g., riding a bicycle at appropriate age)
- Sensory processing and soft neurological problems: sensory processing disorder, sensory defensiveness, under-sensitivity to stimulation
- Social communication: Intrude into conversations, inability to read nonverbal or social cues, “chatty” but without substance
The secondary disabilities of FAS are those that arise later in life secondary to CNS damage. These disabilities often emerge over time due to a mismatch between the primary disabilities and environmental expectations; secondary disabilities can be ameliorated with early interventions and appropriate supportive services.
Six main secondary disabilities were identified in a University of Washington research study of 473 subjects diagnosed with FAS, pFAS (partial fetal alcohol syndrome), and ARND (alcohol-related neurodevelopmental disorder):
- Mental health problems: Diagnosed with ADHD, Clinical Depression, or other mental illness, experienced by over 90% of the subjects
- Disrupted school experience: Suspended or expelled from school or dropped out of school, experienced by 60% of the subjects (age 12 and older)
- Trouble with the law: Charged or convicted with a crime, experienced by 60% of the subjects (age 12 and older)
- Confinement: For inpatient psychiatric care, inpatient chemical dependency care, or incarcerated for a crime, experienced by about 50% of the subjects (age 12 and older)
- Inappropriate sexual behavior: Sexual advances, sexual touching, or promiscuity, experienced by about 50% of the subjects (age 12 and older)
- Alcohol and drug problems: Abuse or dependency, experienced by 35% of the subjects (age 12 and older)
Two additional secondary disabilities exist for adults:
- Dependent living: Group home, living with family or friends, or some sort of assisted living, experienced by 80% of the subjects (age 21 and older)
- Problems with employment: Required ongoing job training or coaching, could not keep a job, unemployed, experienced by 80% of the subjects (age 21 and older)
The following table presents the overlapping behavioural characteristics found between FASD and related mental health diagnoses. Click to open in pdf format.
FASD causes lifelong disability and cannot be cured. Programs exist that can assist with learning and behavioural difficulties. Such assistance can enable a person to maximise their independence and achievements.
Developmental pediatricians will tailor and coordinate individualized treatment programs best suited to each individual.
A wide range of educational and behavioural strategies have been shown to be effective in children with FASD. Stimulant medication may be helpful for the management of attention-deficit/hyperactivity disorder.
Fetal alcohol syndrome usually occurs when a pregnant woman has more than four standard drinks per day. Milder symptoms have been found with two drinks per day during the early stages of pregnancy. Among those who are alcoholic, about a third of children have FAS.
Evidence of harm from less than two drinks per day or 10 drinks per week is not clear. While small amounts of alcohol do not cause an abnormal appearance, it may cause behavioral issues.
The only certain way to prevent FAS is to avoid drinking alcohol during pregnancy. In the United States, in 1981 and again in 2005, the Surgeon General recommended that women abstain from alcohol use while pregnant.
Abstinence was also recommended while planning a pregnancy to avoid damage even in the earliest stages (even weeks) of a pregnancy, as the woman may not be aware that she has conceived.