A new WSU study has found that maternal age and first-trimester drinking by mothers with a history of alcoholism can have substantial effects on their children's IQs. The research has been published in the November issue of Alcoholism: Clinical & Experimental Research.
Numerous studies have documented IQ deficits in children with fetal alcohol syndrome. Little research, however, has found IQ deficits in children with alcohol-related neurodevelopmental disorder, who generally exhibit less severe neurobehavioral deficits than children with FAS. This new work, conducted by Sandra W. Jacobson, Ph.D., a WSU professor of psychiatry & behavioral neuroscience, examines the relationship between selected variables and prenatal alcohol exposure on subsequent IQ. Results indicate that maternal age and first-trimester drinking by mothers with a history of drinking problems can have substantial effects on IQ.
"FAS is characterized by growth retardation, central nervous system impairment, and a distinctive pattern of craniofacial anomalies," Dr. Jacobson said.. "Alcohol-related neurodevelopmental disorder refers to nonsyndromal individuals with confirmed heavy prenatal alcohol exposure who exhibit measurable, but generally subtler neurobehavioral deficits than those seen with FAS. Whereas FAS is well established and easier to diagnose, it is not generally recognized that a child can be adversely affected by prenatal alcohol exposure without the characteristic facial features and growth deficits. Nonetheless, alcohol-exposed children with attention deficits or poor social judgment who lack the pattern of facial dysmorphic features may suffer from a similar set of problems that interfere with their academic and social performance."
Researchers administered the Wechsler Intelligence Scales for Children-III (WISC-III) to 337 inner-city African American children at 7.5 years of age whose mothers were recruited prenatally. (The WISC-III is the most commonly used standardized test of IQ administered to children, ages 6 to 17 years) Alcohol exposure was assessed using a timeline, follow-back interview that was administered to the mothers at every prenatal clinic visit. Numerous potential confounding variables were examined, including maternal education and IQ, smoking and illicit drug use, quality of parenting, maternal depression and psychopathology and current maternal drinking. Researchers also used the Michigan Alcoholism Screening Test to assess severity of psychosocial and physical alcohol-related problems.
This study is the first to demonstrate substantial effects on IQ among children with ARND born to older or MAST-positive mothers, particularly in relation to first trimester drinking, Jacobson said. For children born to women 30 years or older, researchers found an alcohol effect on Full Scale IQ and five of the seven composite IQ scores. Similarly, the study found IQ effects in children born to MAST-positive mothers. For every two additional drinks consumed by the mother per day during pregnancy, researchers found a three-point decrease in Full Scale IQ and a 5.5 decrement on Freedom from Distractibility.
"These findings suggest that there are subgroups of more vulnerable and severely affected children with ARND, whose IQ scores and performance are compromised," Jacobson said.
Dr. Jacobson noted that one very important implication of these findings is that a moderate-to-heavy drinking mother who has given birth to an unaffected child when she was younger needs to be warned that, if she drinks while pregnant, her risk of having an adversely affected child increases as she grows older. This risk is also greater if she has a long-term drinking problem.
"Women in these high-risk groups should be urged to abstain from drinking before becoming pregnant," she said.
Jacobson said that her group's future research will attempt to identify the underlying neural substrates that mediate the effects of alcohol exposure on behavior.