Low―Moderate Prenatal Alcohol Exposure and Risk to Child Behavioral Development: A Prospective Cohort Study

The detrimental effects of fetal exposure to extreme levels of alcohol during pregnancy, such as the subsequent occurrence of childhood physical, cognitive, and behavioral deficits, are well known. Some investigators have suggested that there is a dose-response effect, with light drinking during pregnancy primarily affecting behavioral and adaptive functions and heavy drinking causing more serious developmental defects and problems. Accordingly, mild to moderate social drinking during pregnancy could be associated with long-term infant morbidity. The relatively few studies examining the long-term risk of fetal exposure to light-moderate levels of alcohol have failed to reach consensus, possibly due to deficiencies in study design. This prospective longitudinal cohort study investigated the effect of different levels of fetal alcohol exposure during pregnancy on child and adolescent behavioral development. The Western Australian Pregnancy Cohort (Raine) Study enrolled 2900 pregnancies between 1989 and 1991, with a 14-year follow-up. Maternal self-reported data for 5 levels of weekly alcohol intake were obtained at 18 and 34 weeks' gestation: no drinking, occasional drinking (up to one standard drink per week), light drinking (2-6 standard drinks per week), moderate drinking (7-10 standard drinks per week), and heavy drinking (11 or more standard drinks per week). A linear regression model was used to determine whether prenatal alcohol exposure could produce changes in Child Behavior Checklist scores over 14 years that reflected clinically meaningful differences in child behavioral development, after adjustment for maternal and sociodemographic confounders. Detailed clinical assessments of study children were conducted at birth, with follow-up conducted at 2, 5, 8, 10, and 14 years. The adjusted data showed that light and moderate drinking during the first 3 months of pregnancy resulted in Child Behavior Checklist z-scores indicative of positive behavior over 14 years. The z-scores reflected a clinically meaningful reduction in total, internalizing, and externalizing behavioral problems across the 14 years of follow-up. These findings suggest that low-moderate alcohol intake early in pregnancy is not associated with poor behavioral outcomes in offspring.