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In 1973, K.L. Jones, D.W. Smith and their colleagues
realized that a substantial number of children affected by prenatal exposure
to alcohol exhibited a characteristic set of facial abnormalities, growth
deficiencies, and psychomotor disorders. They named this characteristic
covariance Fetal Alcohol Syndrome (FAS) (Jones et al. 1973). There were so
many different definitions for FAS. The Fetal Alcohol Study Group of
the Research Society on Alcoholism (Rosett 1980) requires presence of signs
in each of three following categories:
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prenatal and/or postnatal growth retardation
(weight, length, and/or head circumference below the tenth percentile
corrected for gestational age) |
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central nervous system involvement (indications
of neurological abnormality, developmental delay, or intellectual
impairment) |
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facial abnormalities (with at least two of the
following signs: head circumference below the third percentile; narrow eye
slits; flat and long upper lip; underdeveloped midface; and flattened nose
bridge) |
Etiology: There is
no safe dose of alcohol in pregnancy and there does not appear to be a
safe period during pregnancy for drinking. It has been shown that mothers
who drink earlier in pregnancy and drink more alcohol (four to ten drinks)
have more children with fully expressed FAS. Mothers who drink less (one
to two drinks) and in late gestation have an increased frequency of
premature deliveries and deliveries of babies small for gestational age.
Risk factors important when assessing the effects of alcohol exposure on
fetal brain development include maternal drinking patterns, differences in
maternal metabolism, differences in genetic susceptibility, timing of the
alcohol consumption during pregnancy, and variation in the vulnerability
of different brain regions. Ethanol is the causative
agent of Fetal Alcohol Syndrome (FAS). FAS is seen in approximately 2 in
1000 live births depending upon culture and socioeconomic status.
FAS does seem to be dose
dependant in that greater amounts of alcohol consumed increases the chances
of having an FAS child. The following are the areas
of brain that are affected by alcohol consumption.
Fig 1: Areas of brain that can be damaged in utero by
maternal alcohol consumption
Source: From Vol. 18, No. 1, 1994 of the journal Alcohol
Health & Research World. Symptoms & Signs:
The most serious characteristics of FASD are the invisible symptoms of
neurological damage that results from prenatal exposure to alcohol, These
symptoms include:
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Attention deficits |
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Memory deficits |
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Hyperactivity |
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Difficulty with abstract concepts |
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Inability to manage money |
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Poor problem solving skills |
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Difficulty learning from consequences |
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Immature social behavior |
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Inappropriately friendly to strangers |
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Lack of control over emotions |
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Poor impulse control |
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Poor judgment |
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Fig 2 : FAS Facial Characteristics.
Source: http:www.come-over.to/FAS/faschar.htm 12/7/2003.
Mechanism of Action:
Alcohol is able to permeate
the placenta and enter fetal circulatory system, thereby causing
developmental abnormalities. Ethanol impairs placental blood flow to the
fetus by constricting blood vessels: inducing hypoxia and fetal
malnutrition. Alcohol rapidly crosses the placenta and blood-brain
barrier of the fetus. The damage produced depends on gestational period,
dosage, and chronicity of abuse.
There are many proposed mechanisms of action for ethanol such as altered
neural crest cell migration/increased neural crest cell death or general
cell death by superoxide radial lysis of cells,
mitochondrial cell dysfunction, may inhibit growth factors
regulating cell proliferation and survival, effects on Glial cells,
effects on development of neurotransmitter systems, effects on cell
adhesion and altered developmental regulation of gene expression. Most of
these proposed mechanisms need to be proved. Recent studies by scientists
of Harvard university in October 2002 proved that alcohol interferes with
L1 adhesion molecules which are useful in cell adhesion process of
development, and hinders the cell to cell attachments. They also found
that the active peptides from NAP and SAL (Brain proteins) protect nerve
cells against a variety of toxins and alcohol. There's still a lot
of research need to be done to finalize the mechanisms of action of
alcohol in the FAS causation.
Diagnosis:
Diagnosis is based on maternal history of alcohol consumption
during pregnancy, abnormalities involving facial features, growth
deficiency, and central nervous system dysfunction. Institute of Medicine
developed criteria to diagnose fetal alcohol related problems.
1.FAS with confirmed maternal alcohol
exposure: Patients in this category
have the classic triad of growth retardation, characteristic facial
dysmorphology and neurodevelopmental abnormalities. This is often defined
as full-blown FAS 2.FAS without confirmed
maternal alcohol exposure: If the
triad described in category 1 is present, a diagnosis of FAS is possible
even without confirmed maternal drinking
3.Partial FAS with confirmed maternal alcohol exposure:
Such patients may have only some of the
characteristic facial anomalies plus growth retardation or central nervous
system neurodevelopmental abnormalities or behavioral/cognitive
abnormalities 4.FAS
with confirmed maternal alcohol exposure and alcohol related birth defects:
Patients in this category will have some congenital anomalies as a result of
alcohol toxicity 5.FAS
with confirmed maternal alcohol exposure and alcohol related
neurodevelopmental disorder: Patients in this category will have
evidence of central nervous system neurodevelopmental abnormalities or a
complex pattern of behavioral/cognitive abnormalities, or both, but not
necessarily any obvious physical changes
Fig 3: Neonatal Meconium assay for fatty acid ethyl esters (FAEEs).
Source: JAMC, 25 NOV 2003, 169 (11), 1184.
Treatment & Prevention:
Treatment: Very little research done on these
topics. Birth defects related to alcohol use are permanent. Surgery can
repair some of the physical problems, and schools and day care centers
offer programs to improve mental and physical development. However,
children born with FAS remain below average in physical and mental
development throughout their lives. Many children with FAS treated for
their individual symptoms (e.g. stimulants for ADHD) and animal data
indicates that early intervention with environmental variables might have
a beneficial effect. Prevention:
 | Primary Prevention: In the case of FAS, this
would include informing the public, particularly young people, about the
dangers of drinking during pregnancy and on a broader level, addressing
determinants of health. |
| Secondary Prevention: Strategies should
include screening and early intervention programs and services for
pregnant women and women of childbearing potential who may be at risk for
having a child with FAS |
| Tertiary Prevention: Strategies should
include diagnosis and programs designed specifically for children with FAS
and their caregivers, as well as treatment for women and their partners
who already have one FAS child and plan to have more children. |
Early recognition of women who drink alcohol during
pregnancy and appropriate counseling are the corner stones of prevention.
health professional play a key role in reducing the risks associated with
alcohol use during pregnancy Surveillance
Programs: CDC is conducting monitoring of FAS
in 5 US states and in South Africa. CDC's FAS Surveillance Network (FASSNet)
is currently conducting monitoring in Alaska, Arizona, Colorado, New York
and Wisconsin. These state programs combine several data sources within each
state to improve likelihood of finding all children with FAS in different
populations and across various geographical areas. the state projects also
educate healthcare professionals about FAS in order to increase early
identification of children with FAS; increase referrals to necessary social,
educational and medical services; and improve documentation of health and
cognitive problems in the children's records.
Wisconsin Fetal Alcohol Syndrome Screening Project:
The Wisconsin Fetal Alcohol Syndrome (FAS) Screening Project (WFASSP) is
a population-based triage ascertainment system with four screen levels. It
is one of five projects funded by CDC to help determine the prevalence of
FAS in the United States. The specific aim of this project is to try out the
screening test so that there is a good way to identify children with FAS
early. The study team also wants to find out how common FAS is and to find
ways of helping these children to develop as normally as possible.
Besides finding out about the screening test, and how common FAS is, this
study aims to identify children who may have FAS so that they can be
referred to services and family support. Children with this condition
benefit from early intervention. |
