SANTA BARBARA, CALIF. – Prenatal alcohol exposure is most likely to affect children's attention problems when it occurs during the third trimester, a prospective study of 492 children determined.
There is a high degree of correlation between teacher- and parent-assessed attention deficits in children exposed to alcohol in late pregnancy, compared with alcohol exposure during the first or second trimesters, Beth Nordstrom Bailey, Ph.D., and her associates reported during the annual meeting of the Research Society on Alcoholism.
“These findings provide yet one more piece of evidence that the timing of prenatal alcohol exposure impacts child outcomes,” concluded the investigators, who presented their study in poster form.
The study from East Tennessee State University in Johnson City, where Dr. Bailey serves on the department of family medicine faculty, carries substantial weight because it prospectively tracked women's substance abuse throughout pregnancy and followed their children for 6–7 years.
The cohort was from urban Detroit and was mostly made up of African Americans with a low socioeconomic status, 90% of whom agreed to participate in the follow-up study.
Caregivers–most often the children's biological mothers–completed the Achenbach Child Behavior Checklist. Classroom teachers completed the Achenbach Teacher Report Form. Both standardized tools include Attention Problems scales.
In a logistic regression analysis, third-trimester prenatal alcohol exposure independently correlated with attention problems as assessed by both caregivers and teachers.
Lead levels and custody changes also correlated with attention scores as assessed by parents and caregivers. Violence exposure factored into the equation only when teachers' assessments were considered.
Prenatal exposure to cocaine, cigarettes, or alcohol during the first and second trimesters failed to independently correlate with later attention problems in children.
In an interview, Dr. Bailey explained that first-trimester exposures have the potential to affect global development of the fetus, possibly resulting in physical deformities, major cognitive impairment, and diminished growth.
In the third trimester, higher order functions are most affected. “It's a time for fine-tuning in pregnancy,” she said. Alcohol exposure during this time appears to affect children's specific attention and behavior functions that can be readily assessed during the school-age years.
Environmental influences also contribute to such problems, but third-trimester alcohol exposure remains a strong correlate even after application of statistical controls for those factors.
“I think this study in particular makes it clear that it's never too late to quit,” Dr. Bailey said. “If at any point in pregnancy a woman can reduce her alcohol consumption or quit, there is still benefit.”
The Center for Healthcare Effectiveness Research at Wayne State University in Detroit contributed to the study, which was funded by the National Institutes of Health and the Children's Research Center of Michigan.