The
pre-natal world of the fetus while cradled in the
mothers womb is sustained in a well-protected
environment, although not immune to the influences of
its external environment. Fetal Alcohol Syndrome which
was first observed by Lemoine et. al (1968)
#1
and was later coined by Jones and Smith (1973)
#2
in Seattle as the fetal alcohol syndrome
(FAS). In a broad sense FAS may be viewed as a
repercussion of an external environmental influence on
the internal physiological environment of the
developing fetus. Alcohol acts as a teratogen (derived
from the Greek word tera, meaning monster), an agent,
which when prenatally exposed can cause serious risks
to pre and post natal human development.
Fetal Alcohol
Syndrome
(FAS) lies at
the extreme end of the continuum of alcohol effects on
the fetus with heavy persistent maternal alcohol
consumption during pregnancy contributing most
significantly to the full blown syndrome. Clinically,
three areas are affected:
(1) prenatal and/or postnatal growth retardation (e.g.
infants shorter in length and less in weight);
(2) Central Nervous System (CNS) damage such as
permanent and irreversible brain damage, learning and
behavioral disorders, deficits in memory and
attention, hyperactivity, speech and language delays,
poor coordination;
(3) head and facial abnormalities (e.g. small head
circumference and abnormally small eyes).
#3
Fetal Alcohol
Effects
(FAE) diagnosed
children have deficits in some or one of the above
three areas of FAS and their mothers were found to
drink smaller daily amounts of alcohol than mothers
who had FAS offspring. #4
FAS were previously estimated, as the third most
frequent cause of mental retardation after Downs
syndrome and certain neural tube defects. Current
prevalence estimates FAS may be the leading most
common, preventable cause of mental retardation in
North America and Europe. In France, Sweden and North
America, prevalence of FAS is 1 per 750 live births
per year. #5
It is expected that FAS children will have some degree
of mental impairment, ranging from minimal brain
dysfunction to severe mental retardation. For every
child identified with FAS, there are several others
who are affected by alcohol exposure but who lack the
full set of characteristics of FAS. FAE is more common
than FAS and is estimated to be 3-10 times that of
those diagnosed with full FAS. #6
Low birth is an example of FAE. It must be noted
that although many other factors can also cause low
birth weight, alcohol is said to account for 2% of the
decreased birth weight associated with prenatal
alcohol exposure. #7
Another example of FAE might be a case where there is
some CNS damage, with signs of speech problems or
attention deficit disorder, but no apparent facial and
head abnormalities. The lack of specific criteria for
FAE makes estimation of incidence statistics and
diagnosis difficult.
Prenatal Alcohol
Exposure
The terms FAS
and FAE are not restricted to the fetal stage as the
names denote. The fetal stage begins around days 46-48
when the first true bone cells replace cartillage.
#8
The period beginning around the 8th week after
conception to birth may be viewed as the fetal stage.
The embryonic stage is the early period between weeks
2-8 after conception. This stage is marked by cell
development or the structural stage in human
development. These cells later differentiate to
produce tissues and organs, which in turn serve bodily
functions, marking the commencement of the fetal
stage. After conception, between weeks 4-8, a
transitory period from the embryonic to the fetal
stage is important as that is a time of great
vulnerability to the toxic effects of alcohol. Many of
the clinical symptoms of FAS are structural (e.g.
facial irregularities which occur in the embryonic
stage). Alcohol also affects the pre-embryonic or
blastocyst stage resulting in delayed implantation and
structural changes. #9
Functional deficits such as damage to the CNS are
usually produced at levels of alcohol exposure lower
than those which would cause structural changes.
Therefore although FAS is found at the adverse end of
the continuum of alcohol effects, the progression of
its symptoms can begin at any point in the course of
prenatal development. Its effects linger postnatally
and are for the most part, irreversible.
#10
Alcohol and
Women: Understanding the Risk
Women Tend to
Metabolize Ethanol Faster than Men .
Alcohol is
soluble in both water and fat, thus it can penetrate
all cell membranes and move throughout all body
tissues. #11,
#12
Passage of ethanol from mother to fetus occurs via the
placenta to a point where fetal alcohol concentration
is almost equal to maternal concentration. FAS/FAE is
then not necessarily the result of only full-blown
alcoholism but rather it can result from drinking any
amount of alcohol in excess of the level to detoxify
it thus placing the fetus at risk. This pattern of
high-risk drinking behaviour is usually reflected
among those who are considered heavy drinkers, but
also may be seen among moderate drinkers who resort to
binge-style drinking.
Women generally
weigh less and have less body water than men making
the volume of distribution of alcohol lower.
Consequently blood alcohol levels can be higher in
women than men when both have consumed equal amounts
of alcohol. Because they frequently experience the
same effects as men with less alcohol, women need to
be informed of the potential hazards of achieving
drinking parity with male drinking companions. Women
tend to metabolize ethanol faster than men.
#13
Recently it was found that women become intoxicated at
a faster rate than men do because their stomachs have
less of the protective stomach enzyme
which is said to breakdown much of the alcohol in the
stomach. Because of this lower amount of protective
enzyme, more of what they drink enters the bloodstream
in the form of pure alcohol. It is said about 30% more
alcohol is absorbed into the bloodstream than in men
as a consequent of having less of this enzyme known
as, alcohol dehydrogenase. Therefore, even when low
doses of alcohol are ingested in men and women, due to
this decreased stomach metabolism, there is more
alcohol availability in women. Over time women are
exposed to higher blood alcohol concentrations than
men are even though similar quantities of alcohol were
ingested. This difference is greater than that
explained by body weight and fat content alone.
#14
Metabolism and
Susceptibility
Studies indicate
differential susceptibility to FAS occurring on both a
racial and genetic basis. We do not know whether
certain ethnic groups have a genetic susceptibility to
FAS even though we do know that there are ethnic
differences in the metabolism of alcohol. We also know
that there is genetic control over the inter -
individual variability in the rate of alcohol
metabolism. In comparison to Caucasians, the Chinese,
Native Americans and Japanese have a higher rate of
alcohol metabolism. #15
Animal studies have shown certain strains of mice
achieve higher blood alcohol levels (BAL) even though
they consume the same amount of alcohol. There is also
evidence of racial differences in acute reactions to
ethanol in terms of alcohol sensitivity symptoms such
as dizziness and hangovers. These were found to be
greater among Orientals of Mongoloid heritage and
American Indians than in Caucasian subjects when
exposed to a mild dose. #15
In this respect
it is possible, that fetal susceptibility to alcohol
may also be dependent upon maternal racial and genetic
compositions interacting with consumption patterns.
The basis of these differences remains to be
determined.
Consumption and
Risk
Occasional
drinking patterns, which are not on a daily or
continuous basis during pregnancy, is not likely to
increase the risk of FAS in offspring. However caution
is advised for daily, light to heavy drinkers, as a
safe level of alcohol consumption during pregnancy has
not yet been established. Research indicates that
increases in the amount of alcohol consumed by a
pregnant woman increased the severity of
alcohols effects in the
offspring.
Heavily drinking
during pregnancy (5 drinks or more daily; average of
3oz. Of pure alcohol per day) places the fetus at high
risk for FAS. Risk for cranofacial anomalies, a
reliable indicator of FAS, was found to increase with
an average intake of 3 drinks daily during the period
following conception and before pregnancy is
confirmed. #16
Occasional
drinking during this period did not increase
risk.
Consumption risk
factors associated with full FAS include increased
number of drinking days, increased daily intake, and
positive MAST scores (Michigan Alcohol Screening Test,
one of the earliest instruments to detect alcoholism)
reflecting an abusive drinking history. In terms of
levels of consumption and risk of FAS offspring, the
literature indicates that risk for FAS increases as
consumption increases over 1oz. absolute alcohol per
day.
Increased
postnatal risk of clinical abnormality in the child at
4 years of age occurs at an intake of about 2oz. or
more of absolute alcohol daily during pregnancy.
#17
Neurobehavioral deficits may occur later and may
result from lower levels of maternal drinking, and
they appear to be more damaging in the long run. Binge
drinking (more than 5 drinks on any occasion) and
drinking during the first two months of pregnancy is
considered to be the two strongest maternal predictors
of postnatal neurobehavioral deficits.
#16
Deficits include hyperactivity, distractability,
speech and language problems.
Alcohol
Consumption during Stages of Pregnancy & Severity
of Effects
The Trimesters:
Blood Alcohol Concentration (BAC), Duration of
Exposure and Dose Level
Each trimester
of pregnancy marks a stage of fetal development and
our understanding of FAS risk needs to be discussed in
light of how the timing of fetal development interacts
with dosage, duration of alcohol exposure and BAC. In
the embryonic stage: the third postconception week of
human pregnancy is considered the critical period for
teratogenic actions of alcohol to produce the most
severe and characteristic features of FAS. Drinking an
average of 3 drinks/daily during the period following
conception and just before pregnancy is confirmed,
increases the risk of having a FAS child. Occasional
drinking during this period did not increase
risk.
The nervous
system develops in the first 8 weeks, making the most
damaging effects result in this period. Although
damage to the brain may occur in the last trimester as
well, vulnerability to brain damage is highest at
15-25 days. #18
There are also two periods of rapid brain growth in
the 3rd month and from the 6th month to after birth.
The CNS, heart, eyes, legs, arms, teeth, ears, palate,
external genitalia are vulnerable to alcohol in the
first trimester.
Malformations
common to these areas suggest that structural damage
commence early.
Research
indicates that among heavy drinkers who continued
drinking throughout pregnancy had offspring with
higher incidence of birth defects than those who
reduced or abstained in the 3rd trimester.
#19
Women who drink moderately throughout pregnancy have
also been found delivering offspring with adverse
outcomes such as an increase in neurobehavioral
problems even in absence of physical facial anomalies
of FAS. #20
Those who drank at moderate levels and discontinued
alcohol use at mid pregnancy fared better than
continuous drinkers. Research findings indicate the
peak BAC increases likelihood of aberrant brain
growth. A key factor in determining severity of FAS
effects may be peak BAC during the third trimester
when it is a critical period for brain development.
Peak BAC can significantly affect the minimum dose
necessary for producing FAE. #21
Conditions such as binge drinking which affect peak
BAC should be curtailed during pregnancy.
Clarrens data on animal studies indicate binge
type alcohol exposure can alter brain function without
physical malformations and this occurs early in
gestation. #9
Peak BAC and
Breast Feeding
Reaching peak
BAC has implications also for breast-feeding. Although
the amount of alcohol ingested by infants through
breast milk is low even when a mother consumes as many
as 4 drinks daily, it is sufficient to cause slight
motor delay. No effect on mental development of fetus
was found at this dosage. Drinking regularly while
breast feeding increases the childs risk of
impaired motor development. #22
Alcohol use during breast-feeding also inhibits
prolactin hormone necessary to maintain lactation.
Alcohol use during pregnancy at moderate levels may
impair childs sucking reflex at birth. Blood
alcohol level threshold slightly below the legal human
intoxication level in the mother results in problems
in maintaining lactation. #23
These problems in feeding inevitably affect the growth
of the infant.
Implications for
Alcohol Education
The importance
of understanding the metabolism of alcohol in women
and how it differs in men, ethnic groups poses
implications on what direction preventive alcohol
education should take.
Alcohol
education targeted to women needs to explain primary
differences between female and male metabolic
processes of alcohol consumption and its consequences
on individual personal health. The next task in
alcohol education is to disseminate to women of
childbearing age, the potential of alcohol as a
teratogen to the embryo and that FAS and FAE are
preventable. As a safe level of alcohol consumption
during pregnancy has not yet been established,
abstinence from drinking while pregnant remains to be
the best precaution, yet not an adequate one,
especially for those women who do not know they are
pregnant until weeks later. This ultimately asks for
looking for common denominators in alcohol education
when designing programs for women of the childbearing
age.
Guidelines are
needed to address sex and drinking as one variable
when they occur as a combination of two variables
acting as one independent variable in a social act or
exchange between individuals similar to the act of
drinking and driving. The trend towards increased
consumption and early sexual activity and teenage
pregnancies places teenage girls at a high-risk group
for delivering offspring with FAS. The inclusion in
alcohol education programs of the potential important
role contraception plays in the prevention of FAS/FAE
is central to targeting women of the child bearing
age. As a depressant, alcohol can do away with
inhibition, which can in turn be conducive to sexual
activity without the use of contraceptives. A Scottish
study which examined contraceptive use and drinking
among teenage men and women, found a decline in
contraceptive use when intercourse was preceded by
alcohol consumption. #24
There is then
the need to address possible outcomes: planned and
unplanned pregnancies in the realm of preventing the
risk of having FAS/FAE offspring, along with the
importance of contraceptive use especially since
research findings have not yet determined a safe level
of alcohol consumption during preconception and
pregnancy.
Among alcoholic
women prevalence of FAS has been estimated at 21 to 29
per 1000 births. A woman who has had a FAS child may
have a recurrence risk as high as 25% more than the
normal population. This risk increases as she
continues to reproduce, being 85 times more frequent
in older siblings of FAS children (170 per 1000) and
350 times (771 per 1000) more frequent in younger
siblings of FAS children than in the general
population. #5
Alcohol drinking
patterns and its interaction with socialization and
sexual experimentation usually gets formalized in the
teen years and progresses into the college and
university settings. The inclusion of FAS in alcohol
education programs at the high school and
university/college level would be vital preventative
education for both male and females. Although much
attention in the research has been placed on maternal
exposure to alcohol, there is some speculation that
the vulnerability of faulty cell development in FAS
may extend to the sperm and not just the female germ
cells. #9
We know that semen of alcoholics have shown to have
aberrant sperm forms resulting in low birthweight as
it occurs in a significantly greater number of
offspring of regular drinking fathers.
#25,
#26
The preventive
goal of alcohol education with the inclusion of topics
on FAS and FAE would best be served if integrated into
relevant disciplines in the school and university
curricula. Life skills learned in planning a family
and in producing offspring integral to a nations
development of qualitative future human resources
would also enable individuals to take responsibility
of their own well-being and of others.