FETAL
ALCOHOL SYNDROME AND OTHER
ALCOHOL-RELATED BIRTH DEFECTS THIS
MAY BE USED AS SUPPLEMENTARY INFORMATION FOR THE TRANSPARENCIES AND POWER POINT
PRESENTATION AN INTRODUCTION TO THE PROBLEM
OF FETAL ALCOHOL SYNDROME (FAS) AND OTHER ALCOHOL-RELATED BIRTH DEFECTS (ARBDs)
When a mother drinks, her unborn child is exposed to alcohol.
As opposed to a common misconception, the baby is not protected in the uterus
from alcohol exposure. Excessive drinking by the mother at any time after fertilization
of the egg may result in damage to the developing child.
The problem of Fetal Alcohol Syndrome (FAS) and other alcohol-related birth defects
(ARBDs) is very large. In fact, maternal alcohol consumption is the leading
known cause of mental retardation in the Western world (transparency #1).
Although the range of intellectual deficits is wide, the average IQ of individuals
with FAS is approximately 70. The prevalence of FAS is typically
quoted as 1 in 750 live births in the general population. However, the reported
incidence varies, depending on the study population and design. The incidence
of FAS currently exceeds that of Down Syndrome, spina bifida, as well as cerebral
palsy. The incidence of all ARBDs, including FAS, is estimated to be 1 in 100
live births in the general population (www.nofas.org,
2004). In spite of the fact that FAS and other ARBDs can
be prevented by women simply avoiding alcohol consumption throughout their pregnancies,
the problem remains. FETAL ALCOHOL SYNDROME (FAS) FAS
is one of several consequences of maternal alcohol abuse. A diagnosis of FAS is
based on the combination of 1) prenatal or postnatal growth deficiency or both
(weight or length or both below the 10 th percentile when corrected for gestational
age), 2) central nervous system disorders including neurological abnormality,
developmental delay, intellectual impairment, and structural abnormalities, and
3) a distinctive pattern of facial anomalies, including short palpebral
fissures, a thin upper lip, an elongated, flattened midface, and an indistinct
philtrum (transparencies #2 &3). Recently, magnetic
resonance imaging (MRI) has made it possible to examine the brains of living individuals
with FAS. Scientists have discovered that the brains of individuals with FAS illustrate
specific structural abnormalities (transparency #4). In addition to deficiency
in the corpus collosum, other areas of the brain including the basal ganglia and
the rostral portion of the cerebellar vermis have been shown to be structurally
deficient. These deficiencies are not reparable. The effects of maternal alcohol
abuse last a lifetime! ALCOHOL-RELATED BIRTH DEFECTS
(ARBDS) FAS represents only a fraction of the consequences
of maternal alcohol abuse. Prenatal alcohol exposure leads to a continuum of reproductive
health effects ranging from infertility, miscarriage and stillbirth to low birth
weight, prematurity, and a variety of neurobehavioral deficits in addition to
physical malformations. Individuals with ARBDs may not have all of the features
noted in those with full blown FAS (i.e. they have fetal alcohol effects, FAE).
They frequently have attention deficits, language difficulties, learning disabilities,
behave impulsively and have poor judgment. Attention deficits are the most consistent
neurobehavioral effect of prenatal alcohol exposure observed in older children.
Cognitive deficiencies and other alcohol-related neurobehavioral deficits are
the most common, but least diagnosed sequellae associated with prenatal alcohol
exposure. Behavioral and mental problems of children with FAE can be just as severe
as those with FAS. Many children with FAS/FAE are not able to understand cause
and effect relationships and long-term consequences. These characteristics predispose
the affected individuals to delinquency. THE
BIOLOGICAL BASIS FOR FAS AND OTHER ARBDS The presentation
of alcohol-induced prenatal damage is dependent on the timing of the insult and
the amount and pattern of maternal drinking (peak blood alcohol concentration).
Although excessive alcohol exposure can cause damage at all stages of in utero
development, the embryonic period (weeks 3-8 after fertilization) is the time
when the conceptus is most susceptible to the development of major abnormalities.
This is not surprising considering that during this short period of time, the
embryo changes remarkably in form. It transforms from a “worm-like”
shape the size of Roosevelt’s ear on a dime at four weeks of development
to the distinctly human form that is the size of a quarter by the eighth week
after fertilization. At early stages, animals such as rodents that researchers
use in order to study the effects of alcohol, are very similar in their development
to humans. This is one of the reasons that the results of experiments on these
laboratory animals can be extrapolated to humans. In fact, exposure of
mouse embryos to a high dose of alcohol at the time of development that corresponds
to the third week of human development (when the human embryo is about the size
of the inside of the 9 in the year “1994” on the dime)can
cause all of the facial features in mice that are typical of children with FAS
(transparency #5). Research has shown that alcohol
can kill cells of the developing embryo. Different cells of the embryo are sensitive
at different stages of development. Some of the cells in the developing brain
and face are particularly sensitive (transparency #6). Finding the pattern
of cell death caused by ethanol at various stages of development provides important
clues for understanding the long-term consequences of maternal alcohol abuse in
affected humans. Research in animals has made it clear that
alcohol can be very damaging even at very early stages of development. In fact,
at some of the early, vulnerable stages, most women are unaware that they are
pregnant. DOSAGE AND WARNINGS
Everyone wants to know “how much is too much”. Although alcohol-related
birth defects are believed to be induced in a dose-response manner, low dose effects
are very difficult to scientifically assess in human populations. Whether there
is a threshold below which alcohol can be consumed without harming the conceptus
is not known. Also, due in part to individual variability (susceptibility), research
will not be able to provide an accurate answer for everyone. To date, studies
indicate that most neurobehavioral effects can be caused by a pregnant woman drinking
from 0.5 to 2 ounces of absolute alcohol per day (7 – 28 drinks with each
containing 0.5 ounces of absolute alcohol per week; an 8 oz. can of beer contains
the same amount of alcohol as a glass of table wine or a serving of fortified
wine or a 1 oz. shot of liquor). Although this would indicate that even one drink
per day can cause measurable consequences to the offspring, the drinking patterns
of many of the women studied were such that the majority of the drinks consumed
in one week were on only one or two occasions, rather that one drink each day.
It is expected that self-reported data showing a relationship between moderate
use and alcohol-related birth defects may often underestimate the true level of
drinking. High peak blood levels of alcohol are important predictors of adverse
outcome. Binge exposures (at least 5 standard drinks on any occasion) result in
a greater frequency of neurological sequellae than the same amount of alcohol
distributed across a greater time course. Certainly, the
best advice is to totally abstain from alcohol use during pregnancy, even at stages
prior to the time that pregnancy is recognized. Although some clinicians believe
that recommending total abstention for pregnant women may subject them to unwarranted
guilt about drinking small amounts of alcohol, most accept the need for clinical
caution. Because it is not known at what dosage alcohol damage begins,
it is prudent to recommend that pregnant women abstain from alcohol use (transparency
#7). In spite of public warnings the Centers for Disease Control reports
a fourfold increase in frequent drinking from 1991-1995 among pregnant women
In addition to considering consequences of alcohol exposure prior to birth, it
is also important to note that alcohol that a lactating mother consumes is present
in her milk and may affect the brain of her nursing infant. ARBDs
are expensive. For one person with FAS, the institutional and medical costs over
a lifetime have been estimated to be between $800,000 to $2 million ( www.nofas.org
, 2004; and Addiction Biology, Vol 9., No. 2, 2004). Recent estimates indicate
that total annual costs of care to US society are as high as $7.8 billion for
individuals with FAS (Addiction Biology, Vol 9., No. 2, 2004). PREVENTION
The traditional ARBD prevention approach of focusing
intervention efforts during pregnancy is after much damage has already occurred.
Physicians and other health care providers should encourage sexually-active childbearing
age alcohol consumers to prevent pregnancy or to avoid any alcohol use during
preconceptional and prenatal periods. Ideally, appropriate
screening of all childbearing age patients for alcohol use combined with preconception
health promotion, contraceptive counseling, and referral to substance abuse programs
for high risk consumers should become a routine standard of care in primary care
settings. Serving this role, physicians and other health care providers will play
a critical role in the primary prevention of FAS and other ARBDs.
Education of physicians, other health care providers, parents, and prospective
parents is essential!!
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