The effect of alcohol binge drinking in early pregnancy on general intelligence in children.

ABSTRACT

OBJECTIVE: To examine the effects of binge alcohol consumption during early pregnancy, including the number of binge episodes and the timing of binge drinking, on general intelligence in 5-year-old children. DESIGN: Follow-up study. SETTING: Neuropsychological testing in four Danish cities 2003-2008. POPULATION A cohort of 1617 women and their children sampled from the Danish National Birth Cohort. METHODS: Participants were sampled on the basis of maternal alcohol consumption during pregnancy. At 5 years of age the children were tested with six subtests from the Wechsler Preschool and Primary Scale of Intelligence - Revised (WPPSI-R). Parental education, maternal IQ, prenatal maternal smoking, the child's age at testing, the gender of the child, and tester were considered core confounding factors, whereas the full model also controlled for prenatal maternal average alcohol intake, maternal age, maternal pre-pregnancy body mass index (BMI), parity, home environment, postnatal parental smoking, health status, and indicators for hearing and vision impairment. MAIN OUTCOME MEASURE: WPPSI-R. RESULTS: There were no systematic or significant differences in general intelligence between children of mothers reporting binge drinking and children of mothers with no binge episodes, except that binge drinking in gestational weeks 1-2 significantly reduced the risk of low, full-scale IQ (OR 0.54; 95% CI 0.31-0.96) when adjusted for core confounding factors. The results were otherwise not statistically significantly related to the number of binge episodes (with a maximum of 12) and timing of binge drinking. CONCLUSIONS: We found no systematic association between binge drinking during early pregnancy and child intelligence. However, binge drinking reduced the risk of low, full-scale IQ in gestational weeks 1-2. This finding may be explained by residual confounding.