Alcohol Exposure During Pregnancy
Links to Learning Disabilities, ADD and Behavior Disorders
The following is one chapter from a 1997 Graduate Student Research Project
conducted at the
Author: Richard W. Pressinger (M.Ed.)
New Warnings as
Even Low & Moderate Use of Alcohol During Pregnancy
Alcohol - Pregnancy
Click Title to View Article Summary
Below is a listing of what we have found to
be the most significant research articles
on the effects of alcohol upon the developing embryo and fetus during pregnancy
|Introduction to Alcohol Use
What is safe? - How bad is the problem? - Whose Drinking During Pregnancy?
|Severe Brain Damage to Children
Graphic pictures of what alcohol can do in high levels to the brain
|One Binge Drinking Episode Causes Fetal Alcohol Syndrome - FAS|
|Fetal Alcohol Syndrome (F.A.S) After Moderate Alcohol Drinking|
|Attention Deficit Disorder & Distractibility|
|Developmental Delays -|
|Reading Test Scores Lower|
|Language & Speaking Delays
Consuming even one-half drink daily appears to damage speech centers
|Evidence of "Sooner Than Expected" Memory Loss in Adult Brains|
|Attention Deficit Linked to Neurotransmitter Dopamine|
|Neurotransmitter Reductions in Acetylcholine Levels|
|Alcohol Damages Learning Brain Area Known as Basal Ganglia|
|Attention Deficit & Hyperactivity Linked|
|Alcohol Damages Brain Cells called Astrocytes|
Unfortunately, there are still a few physicians today who believe that low levels of alcohol will not harm the fetus. Some even suggest that one glass of wine is "OK" during pregnancy. Their assumptions are based upon the fact that low levels of alcohol do not appear to cause any increased risk of physical malformations to the fetus. Although, this line of thought is correct, more recent research shows birth defects can also take the form of something other than a visual physical abnormality such as a malformed leg, arm or finger.
In fact, another type of birth defect not usually associated with the term "birth defects" is called a neurological defect and can occur from subtle alterations in brain organization or chemistry during pregnancy. The consequences of such a defect can appear later as a behavior problem, learning disability, attention deficit disorder, hyperactivity, aggression, violent tendencies, impulsivity or even reduced personality and increased shyness. Any of these traits could then be considered a neurological birth defect -
..if the personality trait resulted because of altered neurological development due to an environmental exposure during pregnancy.
Figures reported by Dr. Nancy L. Day, of the University of Pittsburgh show at least one reason why child learning disabilities and behavior disorders are higher than 30 years ago. The percentage of what is defined as "heavy" alcohol drinking has risen from 4% of all pregnant women in 1964 to 5% of all pregnant women in 1988. The percentage of pregnant women who are "binge-drinkers" (more than 5 drinks per day) has risen 50% in just 20 years, going from 4% of all pregnancies in 1964 to 6% in 1984.
These figures alone should generate serious concern as even one occurrence of alcohol binge drinking has been linked with damaging a childs developing brain (this is outlined in one medical summary below).
It wasnt until 1973 that the name Fetal Alcohol Syndrome (FAS) was given to describe the specific pattern of neonatal birth defects that occurred in children whose mothers consumed large amounts of alcohol during pregnancy. It is now estimated that 1 in 1500 births to alcohol consuming women can result in obvious FAS, although many variables such as amount of alcohol, timing of drinking and mixing of substances can greatly increase the odds of having a FAS child.
Only three scientific or medical papers were published on FAS in 1973, however, by 1979 the annual publication rate for FAS was more than 200 and by 1985 the total output approached 2,000.
FAS is characterized by a group of congenital birth defects that include the following:
Prenatal and postnatal growth deficiency
Small head circumference
Sunken nasal bridge
Flattened and elongated philtrum
Central nervous system dysfunction
Varying degrees of major organ system malformations.
More moderate effects upon the brain can also occur from prolonged alcohol exposure to the unborn child. Alcohol can cause the loss of what is called dendritic spines (connections between brain cells) in an area of the brain known as the hippocampus - an area important for learning and memory (Science, 201:646-648, 1978 ). In animal models, alcohol is embryotoxic (toxic to the embryo) and teratogenic (able to cause physical birth defects), and it has been demonstrated that behavioral as well as biochemical abnormalities occur in animals exposed to alcohol during pregnancy.
Severe Child Brain Damage Due to Mother's Alcohol Drinking
Journal of Pediatrics, 92(1):64-67
The brains of four children born to drinking mothers were studied for abnormalities after their deaths at the University of Washington School of Medicine. One child was stillborn, the other children died at three days, six weeks and 10 weeks. Death in all cases was due to the complications caused by the mothers alcohol drinking.
The photograph at left shows the brain of an infant girl who died at 6 weeks. The mother was categorized as a chronic alcoholic. The childs head circumference was 27 centimeters at birth and did not grow at all during her 6 weeks of life (normal head circumference is approximately 35 centimeters - about 13 and 3/4 inches).
Readily observable is a massive sheet of tissue that covered the left cerebral hemisphere. Microscopic investigations showed some areas of the left cortex were "uniformly thinned and disorganized." There was an increased cell density in the second layer of the superficial cortical layers (top of the brain) and decreased cell density in the third layer, demonstrating errors in the migration process of brain cells. The researchers also found that in scattered areas of the cortex the neurons showed "bizarre arrangements."
Case number 2 was a male infant born at term and died at 10 weeks due to a sudden cardiac arrest (see picture at right). The mother's alcohol drinking included up to a gallon of wine at a time several times a week. The child had hydrocephalus (excess water in the brain) and typical facial features of fetal alcohol syndrome (FAS). The cerebellum (which controls coordination and movement) was "extremely small and poorly shaped (see picture at right)." The brainstem (responsible for processes such as breathing and body temperature) was also grossly malformed.
Case number 3 was stillborn at the 29th week of pregnancy. The mother reported drinking alcohol beverages at approximately weekly intervals, sometimes consuming at least five "drinks" at one time. The child had most of the features of FAS, including short palpebral fissures, flat midface, cleft lip and palate. The testicles were also absent. The cerebrum appeared normal except for overly large ventricles (the ventricles are fluid cavities in the brain which help maintain constant pressure). The researchers stated the brainstem and cerebellum were "unfortunately lost" prior to microscopic study.
Case number 4 was a premature infant born about two months early. The mother reported drinking alcohol three or four times each week, sometimes consuming at least five "drinks" at one time. The child suffered respiratory distress and died three days after birth. Although the brain weight of the infant was normal and no features of FAS were apparent, there was the similar smooth covering of the left cerebral hemisphere as shown in the picture of the first infant.
In a discussion of these observations, the researchers stated:
"Necropsy studies on four perinatal subjects exposed to high peak volumes of ethanol during gestation have demonstrated similar types of problems in brain morphogenesis (brain development).... The most frequent type of brain malformation among the affected subjects was a leptomeningeal, neuroglial heterotopia, which is a sheet of aberrant neural and glial tissue that covers part of the brain surface and may partially incorporate the pia matter. Such surface heterotopias were found on the brains of cases 1,2, and 4. In two of the three cases completely studied histologically there was extensive brain disorganization resulting from errors in other neuronal and glial migrations.... According to current understanding of normal neuronal migratory timing, interference with cerebellar and brainstem development occurred prior to 45 days gestation in these cases. The cerebral abnormalities were initiated by 85 days gestation.... The mechanisms through which alcohol might interfere with brain morphogenesis is not yet understood, but it would appear that intermittent high peak doses of ethanol can cause damage. The severity in effect probably relates not only to dosage but to gestational timing and individual fetal response as well.
Drs. S. Clarren, E. Alvor, Jr., M. Sukmi,
A. Streissguth, D. Smith
Fetal Alcohol Syndrome
Science, November 20, 1981
Much information has been accumulated on the chronic consumption of alcoholic beverages and its effects upon the developing child. However, research from the University of North Carolina at Chapel Hill, suggests that even one drinking session of 5 or 6 drinks early in the pregnancy could be enough to cause mental retardation and many of the facial defects associated with fetal alcohol syndrome. Although most studies of FAS pinpoint long term heavy use of alcohol, the researchers at Chapel Hill suggest a two or three day "critical period" as early as a few weeks after conception when the developing human fetus is especially vulnerable to alcohol effects. The test animals were given only two doses of alcohol about four hours apart at the very beginning of their pregnancy. The level of alcohol given to the test animals was equal to about twice the "legal limits" allowed in humans for DUI. While examining the fetuses a week later, the researchers found facial defects, eye malformations and abnormally small brains in nearly 50% of the mice.
Drs. Kathleen K. Sulik, Malcolm C.
Johnston and Mary A. Webb
Fetal Alcohol Syndrome
Journal of Pediatrics, 92(3):457-460
Results from a study of moderate alcohol intake during early pregnancy suggests problems for the developing infant. A study of 163 middle class, predominantly white children were selected from two Seattle, Washington hospitals. They were investigated for any abnormalities by a physician, who was unaware of the parents drinking background. The assessment included looking for, (1) small size for gestational age (weight or length or both less than third percentile); (2) microcephaly (head circumference less than third percentile); (3) short palpebral fissures (eye openings with width less than 1.8 cm in infants >36 weeks gestational age; and (4) abnormal features in two of the following which included either: broad, low nasal bridge, epicanthic folds, long philtrum, small nails, limitation of joint movement, cardiac murmurs and ear anomalies. On the basis of the above ratings, each newborn infant was placed into one of three clinical categories: (A) Features compatible with fetal alcohol syndrome; (B) Minor abnormalities not indicative of FAS; and (C) normal. After the assessment by the physician was matched with the parental drinking habits, the following results were determined:
10% risk of having abnormal or
19% risk of having abnormal
The figures above show the serious problem posed by drinking mothers. These figures are not 10% and 19% increased risk figures for having an abnormal or FAS child but are the actual risk figures. In other words, the study showed that if the mother drank 2-4 drinks daily - she had a 1 in 10 chance of having an abnormal or FAS child and if she drank more than 4 drinks daily she had nearly a 1 in 5 chance of having an abnormal or FAS child. Previous reports have suggested that in chronic alcoholic women (usually more than 5-6 drinks daily) the risk of producing a clinically abnormal child (not necessarily a complete FAS) may be 40% or more. Also, the researchers stated that the observation that drinking behavior in the immediate prerecognition of pregnancy period is more strongly related to fetal outcome suggests that the quantity and timing of alcohol intake in the earliest stages of pregnancy have important implications for fetal growth and development.
The researchers concluded,
Dr. James W. Hanson
Attention Deficit &
Neurobehavioral Toxicology and Teratology, 8:717-725, 1986
Attention, distraction and impulsive behavior problems were found to occur more often in a study of 475 young school age children whose mothers drank moderate amounts of alcohol during pregnancy. The study, conducted by the University of Washington, used sensitive neurological test measures, called Continuous Performance Tasks (CPT), to determine endurance, persistence, organization, distractibility and impulsivity in this large group of 7 year old children.
One test given, considered to be effective at assessing Attention Deficit Disorders, is called the AX-task. In this test the child sits at a computer screen that is flashing single letters at one second intervals. The child is asked to push a button when the letter "X" appears, but only when it was immediately preceded by the letter "A". The number of errors were then calculated for three different mother alcohol consumption levels (0-3 drinks daily, 3-4 drinks daily, & more than 4 drinks daily) to determine if there was any correlation between the amount of alcohol consumed and the number of errors the child made on the test.
The results showed that greater alcohol exposure resulted in far more errors on the AX task. The authors stated that, "The direction of the effect is as predicted, with poorer performance associated with higher (alcohol) exposure."
Tests of distraction were also conducted while the child was taking the CPT tests. There was an 8% distraction rate for the 0-3 drink exposure children, a 14% distraction rate for the 3-4 drink exposure children and a 46% distraction rate for the children whose mothers drank more than 4 drinks per day. Average reaction times were about twice as slow for the more than 3 drink exposure children. In conclusion the researchers stated,
Dr. Ann P. Streissguth, Helen M. Barr, Paul D. Sampson
A variety of neurological and school problems were detected among 500 children examined at numerous points in time, including day 1 and 2 of life, at 8 and 18 months, and then again at 4, 7 and 14 years. Mothers were primarily white, middle class, well-educated, married women at low risk for adverse pregnancy outcomes. Approximately 80% were drinking. The study, headed by Dr. Ann P. Streissguth, Department of Psychiatry and Behavioral Sciences, University of Washington, lists the following principal findings:
Reading Test Scores Lower
Neurotoxicology & Teratology, 13:357-367, 1991
Significant reductions in several areas of intellectual functioning were found in preschool children whose mothers drank during pregnancy. The study, conducted by the Emory University School of Medicine and Georgia Mental Health Institute, looked at 68 mother/child pairs, primarily low income and black, who were placed into three groups including: "never drank" (21 mothers), "stopped drinking" (22 mothers who stopped drinking just before the third trimester), and "continued to drink" (25 mothers who were exposed throughout pregnancy). The women did not use other drugs except for cigarette and marijuana use in about 12%. Average alcohol intake for both alcohol drinking groups was 2-3 drinks per day with approximately 21% of the women engaging in "binge" drinking episodes of more than 5 drinks per occasion.
Main results of the survey showed childrens head circumference was much lower in the drinking groups measuring 34.7 cm for the "never drank" - 33.3 cm for the "stopped drinking" - and 32.4 for the "continued to drink" (over 2 cm difference between the "never drank" and "continued to drink" groups). Scores for math and reading/decoding were also significantly lower for the alcohol exposed groups. Using the Kaufman Assessment Battery for Children, the researchers calculated a math score of 96.5 for the "never drank" group, 86.7 for the "stopped drinking" group and 84.8 for the "continued to drink" group (nearly a 12 point difference). Reading/decoding scores were significantly lower only for the "continued to drink" group dropping from 101.8 to 91.6 suggesting the importance of neurological growth in the "reading areas" of the developing brain during the last 3 months of pregnancy.
Also, the test of sequential processing skills was much lower for the alcohol groups which included subtests for hand movement and reciting numbers and word order, each of which is stated to require short term memory processing. Short term memory processing, often called encoding, is believed to be supported by the subcortical structures of the brain including the hippocampus, which are particularly susceptible to the effects of alcohol according to research in the Archives of Neurological Psychiatry Vol. 79(5):475-497.
In conclusion, the researchers stated,
Dr. Claire D. Coles, Human And Behavior Genetics
Laboratory, Department Of Psychiatry, Emory University School of Medicine
Language Skills Damage Easily from Light Social Drinking
Neurobehavioral Toxicology & Teratology, 6:13-17, 1984
Lower verbal comprehension and spoken language scores were found among 84 children at 13 months of age whose mothers drank an average of .24 ounces of absolute alcohol per day (about one-half drink per day). The Bayley Scales of Infant Development was used to test language and comprehension. Test criteria included the following:
Testing was given by a trained professional who was not aware of the mothers drinking habits. The researchers adjusted for known confounding variables such as social class, educational level, use of other drugs, etc. Results were considered significant at the p<0.05 level.
Drs. Joanne L. Gusella and P.A. Fried
Early Memory Loss
Neurotoxicology & Teratology, 16:283-289, 1994
The researchers stated that for the first time in alcohol brain research, it was found a single large dose of alcohol to pregnant rats resulted in memory loss to their offspring, but only after the offspring reached 2 years of age (This would be equivalent to a middle age human). The testing was set up with three different age groups of alcohol exposed rats (3 months, 12 months & 24 months) that were each exposed to a single large dose of alcohol while their mothers were pregnant.
Each different age group of alcohol exposed rats was first thoroughly taught the escape route to a semi-complex maze. The rats were then tested 24 hours later and then again after about 3 weeks to see if they still remembered their way out. All rats remembered their way out after this 24 hour period. However, what was interesting was that after a little over 3 weeks, only the older, 24 month old rats had a difficult time remembering their way out. In fact, the 2 year old alcohol exposed rats made an average of 18 errors in the maze, while the old rats not exposed to alcohol during pregnancy made on average only about 10 errors. The researchers stated this experiment clearly demonstrates damage to the long term memory centers of the aging rats that occurred sometime during their mothers alcohol exposed pregnancy and is believed to be extremely subtle since no other obvious effects were observed in biological examinations.
Dr. Ruth M. Dumas
Disorder (A.D.D.) Link
Neurobehavioral Toxicology & Teratology, 6:19-21, 1984
Dopamine is a neurotransmitter essential for proper brain function. It is believed to play an important role in motor function and has been found in lower levels in children with ADHD. In a study conducted at the University of Milan, Italy, it was found that a single dose of alcohol given on the 4th day of pregnancy to 10 rats "dramatically reduced" the levels of "striatal dopaminergic receptors" in their offspring (the striatal part of the brain includes the cerebral cortex). In fact, the alcohol exposed offspring had only about half the concentration of the dopamine metabolite DOPAC in their brain tissue when compared to the non-alcohol exposed controls (1.09 ng/mg compared to 2.03 ng/mg). Of interest, the same dose of alcohol given on the 13th day of pregnancy did not change the concentration of this dopamine metabolite DOPAC. The researchers explain this timing observational change since the rats brain (particularly the dopaminergic system) is developing rapidly on the 4th day and is nearly complete by the 13th day. The 4th day in a rats pregnancy would coincide with the first month of a human pregnancy.
Dr. Laura Lucchi, Vito Covelli
Brain Neurotransmitter Reduced After Alcohol Exposure
Journal of Neurochemistry, 28:1175-1182, 1977
Acetylcholine is a neurotransmitter that is important in all brain cell functions, including proper memory function. In this research project, after rats were exposed to alcohol for prolonged periods it was found their acetylcholine levels were 25% lower than rats not exposed to alcohol.
Dr. A. K. Rawat et al
Abnormal Brain Area (in
Neurotoxicology & Teratology, 16(3):283-289, 1994
Using brain scanning techniques called Magnetic Resonance Imaging (MRI), scientists have shown various neurological abnormalities among Fetal Alcohol Syndrome (FAS) children including - microcephaly (small head size), and reduced volumes in the cerebellum (brain area at the back of the head controlling coordination and movement), basal ganglia, and the area known as the diencephalic structures. Also, abnormalities have been identified in the nerves connecting both halves of the brain called the corpus collosum.
In this present study, scientists from three California research universities including San Diego State University, University of California San Diego School of Medicine and the Scripps Research Institute, pooled their talents to investigate whether similar brain abnormalities would be present in non-FAS children whose mothers drank heavily during pregnancy.
In the present study, researchers investigated two 16 year old children (1 male, 1 female), who did not have FAS but whose mothers were considered "alcoholic" and drank heavily during pregnancy. Both children also had a history of behavior problems and cognitive impairments. Their IQ scores were 64 and 69.
Doctors stated results from the MRI scan of both children showed,
The authors further stated,
In a follow-up study, the scientists studied 20 male mice exposed to alcohol during gestation. Autopsy results of the animals brains showed a smaller caudate-putamen area.
The authors stated,
Drs. Sarah N. Mattson, Edward P. Riley, et
Hyperactivity - A.D.D.
and Behavior Disorders
Journal of Pediatarics, 96:978, 1990
A study was conducted with 15 children from the Yale Learning Disorders Unit whose mothers were known to have a history of heavy drinking during pregnancy. The 11 boys and 4 girls ranged in age from 6 to 18 years of age. Physical measurements showed that 60% of the children had a head circumference less than the 10th percentile (the term 10th percentile means 10% of the children should be expected to be below this level) while 20% of the children were below the third percentile. FAS is now reported to be the third most frequent disorder in which retardation is a component. The physicians at the Yale Learning Disorders Unit stated,
The intent of their research was to investigate the growth, cognitive function and school performance in a group of learning-disabled children of normal intelligence born to heavy drinking women. It is the recommendation of the physicians that children experiencing school failure should be evaluated for indications of prenatal exposure to alcohol. Cognitive performance was measured using the Stanford Binet form L-M , the Wechsler Pre-School and Primary Scale of Intelligence and the Wechsler Intelligence Scale for Children. Although all children had a mean full scale IQ of 98.2, there were other problems with school performance. Hyperactivity was evident in all but one of the patients school reports. Six were taking stimulant medication for their condition. The poorest scores on the intelligence tests were in the areas of coding, arithmetic, digit span memorization and information subtests. In conclusion the authors stated,
Sally E. Shaywitz, M.D., Donald J. Cohen, M.D.,
Damage to Astrocyte Brain
Neurobehavioral Toxicology & Teratology, 8:17-21, 1986
Changes in neurons in experimental and human brains have been well documented after exposure to varying levels of alcohol. However, another type of brain cell, called an astrocyte, has been found to suffer reduced quality after even very low levels of alcohol exposure. In fact, researchers in this present study state, "Derangements in astrocyte growth and differentiation may be major contributors to the pathogenesis of brain abnormalities in the fetal alcohol syndrome."
Briefly, according to research By Dr. William Pardridge at University of California, Los Angeles, astrocytes serve a very important support role to our "thinking" primary brain cells called neurons, one of which is to literally pull nutrients from surrounding blood vessels and transport them to the neurons, almost like a vacuum cleaner. Another important role is to serve as the first stage to the "blood brain barrier" by attempting to detoxify toxic compounds that enter the blood, although the mechanism is far from fool-proof. Astrocytes are believed to be one of the first brain cells to develop in the fetus.
In their research to determine the effect of alcohol on astrocyte growth, Dr. L. A. Kennedy and colleagues at the College of Medicine, University of Saskatchewan, Canada placed approximately 600,000 newborn mouse brain cells into nutrient rich petri dishes to evaluate growth patterns after low level exposure to four alcohol concentrations (.0, .06, .12, .24 g/dl). These levels were chosen because they represent a range of alcohol levels to which the embryo and fetus might realistically be exposed in the uterus during periods of mild to severe states of maternal alcohol intoxication. After letting the cells establish themselves for 6 days, the researchers then exposed the brain cell groups to the varying alcohol levels for either 4 days (Experiment 1), 11 days (Experiment 2), 18 days (Experiment 3) and for the last brain cell group (Experiment 4) they waited 20 days before beginning a short 4 day exposure to the different alcohol levels.
The researchers stated the following results from their experiments,
Dr. L. A. Kennedy and S. Mukerji