P., Barr, H. M., & Sampson, P. D. (1990). Moderate Prenatal Alcohol Exposure: Effects on Child IQ
and Learning Problems at Age 7 1/2
Years. Alcoholism: Clinical and Experimental Research, 14(5), 662-
Researchers were interested in
whether the central nervous system (CNS) effects of prenatal alcohol exposure
would be observable in 7-year-old children on tests of intelligence and
learning problems. Researchers hypothesized that the learning and IQ problems
evidenced by the children were a result of alcohol exposure during pregnancy as
opposed to postnatal environments.
Previous studies have shown that
children without fetal alcohol syndrome who were still born to chronically
alcoholic mothers were at a higher risk of growth deficiencies and lower IQ.
More recent studies on rats have shown that ethanol effects on brain
development could account for some long-term neurobehavioral effects observed
in humans. Other studies with human participants have also demonstrated
neuropsychological and attention deficits in children who were heavily exposed
These studies have also ruled out
any other biological factors that are sometimes associated with maternal
alcoholism, such as poor nutrition or zinc deficiency.
Sample and Population
study began with prenatal interviews of 1,529 pregnant women in Seattle. A high
percentage of the mothers were white, married, and middle-class. Women who
agreed to be a part of the study (85%) were then interviewed in their own home
in regard to their alcohol use, caffeine use, and tobacco use, along with
questions about their nutrition, pregnancy histories, and demographics. The
researched screened for women who were heavier drinkers, and lowered their
sample size to around 500 women, including about 250 women who were the
heaviest drinkers, and about 250 women who were abstainers or infrequent
drinkers to act as a control group. There were a total of 482 children that
were evaluated for the study, and were evaluated on the first and second days
of life, at 8 and 18 months, and at 4 and about 7 years of age.
The key alcohol scores were used as
the primary independent variable and reflected the varied patterns and levels
of consumption reported by the mothers. Average ounces of alcohol per day
during pregnancy reflected overall exposure.
The dependent variable was the
children’s performance in different tests and ratings. The dependent variable
was assessed using summary scores on IQ and achievement tests (Full Scale IQ,
the Verbal Scale IQ, and the Performance Scale IQ), teacher ratings on a
learning disabilities scale, parent ratings on child’s school performance, and
child’s participation in remedial programs. Researchers also examined several
indicators of learning problems such as hyperkinesis and impulsivity.
Control variables were also assessed
and included maternal age, race, and parity; maternal use of cigarettes,
marijuana, caffeine, and nutrition during pregnancy; breast feeding; family
history of learning disabilities; life stress in the home; and child’s sex,
grade, and age at testing.
Research findings showed that the
children’s performance was very good in general for the full cohort of 482.
However, the three IQ tests that were conducted on the children were all
significantly lower for the children exposed, on average, to greater than 1
ounce of alcohol per day in midpregnancy. In regard to academic achievement,
prenatal alcohol correlated with reading and arithmetic, but not spelling. This
was largely correlated to women in the BINGE category, meaning they reported
five or more drinks on any occasion, which resulted in their children being 1
to 3 months behind their peers in reading and arithmetic.
Researchers also found that “24% of
the children of binge drinkers were participating in special remedial programs
at school verses 15% of the children of nonbingers” (Streissguth et al., 1990, p. 666). 17% of the
children of binge drinkers also had MPRS scores below 65, meaning that their
schoolteachers believe they were at risk for learning disabilities. Researchers
concluded that the study indicates measurable effects of prenatal alcohol
exposure on IQ scores, achievement test scores, and learning problems, at early
Strengths and Limitations
One of the greatest strengths of
this study is that it is the first study to link learning problems in young
school children with social drinking during pregnancy. The researchers also did
a good job of including many IQ tests in order to gather from multiple sources
of data, leading to a more accurate assessment of each child’s IQ.
In spite of these strengths, there
were also some limitations in the study. The sample and population consisted of
mostly white, middle-class families, and the results may not translate to a
more diverse population. Another potential limitation or weakness is that there
were other covariates that made an impact on the child’s IQ, such as low
paternal education and more children in the household.