Prenatal alcohol exposure appears to cause later conduct problems in childhood, reported Dr. Brian M. D'Onofrio of Indiana University, Bloomington, and his associates.
In contrast, the later attention and impulsivity problems seen in children who were exposed to alcohol in utero appear to be caused by other factors correlated with maternal drinking rather than to the alcohol exposure itself, the researchers said.
Dr. D'Onofrio and his associates used data collected in a large longitudinal study of adolescents and young adults to examine the relationship between drinking in young women and behavior in their offspring. The survey, funded by the U.S. Bureau of Labor Statistics, covered a racially diverse sample of more than 6,000 subjects who were assessed annually from 1979 through 1994 and then biannually since then (Arch. Gen. Psychiatry 2007;64:1296–304).
Dr. D'Onofrio and his associates analyzed data on a subsample of 4,912 young female subjects who had at least one child aged 4–11 years by the 2004 assessment. The women had furnished information on their substance use both before they had become pregnant and during their pregnancies. They then reported on their children's conduct problems and attention/impulsivity problems using the Behavior Problem Index.
Prenatal exposure strongly correlated with conduct problems, and children with exposure to higher levels of alcohol had more such problems than those exposed to less alcohol. Compared with children who were not exposed to alcohol in utero, those who were exposed to alcohol every day had an increase of 0.35 standard deviations in conduct problems.
This link persisted after the data were adjusted to account for potentially confounding factors such as prenatal exposure to nicotine and other drugs, maternal traits, and genetic and environmental factors. It also persisted in comparisons with siblings and cousins, and in a number of statistical models.
“The results of all models are consistent with a causal association between prenatal alcohol exposure and offspring conduct problems,” the investigators said.
In contrast, prenatal alcohol exposure did not appear to be causally related to attention/impulsivity problems, although these problems were highly prevalent in exposed children. It is likely that some other factor related to maternal drinking explains this association, they added.
This large-scale study complements but does not replace more focused studies that can more accurately assess the particular mental health problems in children who were exposed to alcohol prenatally, Dr. D'Onofrio and his associates noted.