Prenatal exposure to alcohol and conduct problems: A clearer link
An Indiana University study provides some of the strongest evidence yet that prenatal exposure to alcohol causes conduct problems in children, a finding that has been called into question in recent years.
A national study involving 4,912 mothers and 8,621 of their offspring documents the connection between the mothers' moderate drinking during pregnancy and later conduct problems in the children they carried while drinking. Conduct problems include such behaviors as intentionally breaking things, bullying, cheating and lying.
The study, lead by Brian D'Onofrio, assistant professor in IU Bloomington's Department of Psychological and Brain Sciences, found that conduct problems in children increased for each additional day of the week on average that the mother drank while pregnant.
The study, "Causal Inferences Regarding Prenatal Alcohol Exposure and Childhood Externalizing Problems," was published on Monday (Nov. 5) in the journal Archives of General Psychiatry.
D'Onofrio said the study was able to rule out a host of other explanations for the conduct problems in part because the study included multiple children per mother, which allowed researchers to look at siblings who were exposed differently to alcohol prenatally because their mothers varied their drinking during different pregnancies. The study found that children more frequently exposed to alcohol during pregnancy had more conduct problems than their siblings who were exposed to less prenatal alcohol.
D'Onofrio and his co-authors wrote that prevention efforts should continue targeting alcohol consumption during pregnancies.
"What's most concerning now is that a large number of women in their child-bearing years are drinking when they don't realize that they're pregnant," D'Onofrio said.
D'Onofrio and his colleagues analyzed data about mothers enrolled in the National Longitudinal Survey of Youth. Yearly from 1979 until 1994 and then biennally through 2004, the women answered questions about their substance use during each of their pregnancies. The researchers also analyzed data involving the mothers' offspring, who were part of the Children of the National Longitudinal Survey of Youth. Children ages 4-11 were assessed biennially for behavior problems, beginning in 1986. The study was supported by the National Institute of Mental Health.
In addition to examining conduct problems, the researchers looked at the connection between prenatal exposure to alcohol and attention and impulsivity problems. Children whose mothers drank alcohol during pregnancy also had more attention and impulsivity problems, according to the study. The researchers did not find a difference in siblings' behavior, however, when the mothers drank more while pregnant with some siblings than others. The siblings had the same level of difficulty with attention and impulsivity regardless of their prenatal exposure to alcohol.
Co-authors of the study are Carol A. Van Hulle, Paul J. Rathouz and Benjamin B. Lahey, all with the Department of Health Studies, University of Chicago; Irwin D. Waldman, Department of Psychology, Emery University; and Joseph Lee Rodgers, Department of Psychology, University of Oklahoma.