Objective To examine the effects of low to moderate maternal alcohol consumption during early pregnancy on children's intelligence (IQ) at age 5 years.Design Prospective follow-up study.Setting Neuropsychological testing in four Danish cities 2003-2008. Population A cohort of 1628 women and their children sampled from the Danish National Birth Cohort.Methods Participants were sampled based on maternal alcohol consumption during pregnancy. At 5 years of age, children were tested with the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R). Parental education, maternal IQ, maternal smoking in pregnancy, the child's age at testing, gender, and tester were considered core confounding factors, whereas the full model also controlled for maternal binge drinking, age, BMI, parity, home environment, postnatal smoking in the home, health status, and indicators for hearing and vision impairments.Main outcome measures The WPPSI-R.Results No differences in test performance were observed between children whose mothers reported consuming between one and four or between five and eight drinks per week at some point during pregnancy, compared with children of mothers who abstained. For women who reported consuming nine or more drinks per week no differences were observed for mean differences; however, the risks of low full-scale IQ (OR 4.6; 95% CI 1.2-18.2) and low verbal IQ (OR 5.9; 95% CI 1.4-24.9) scores, but not low performance IQ score, were increased.Conclusions Maternal consumption of low to moderate quantities of alcohol during pregnancy was not associated with the mean IQ score of preschool children. Despite these findings, acceptable levels of alcohol use during pregnancy have not yet been established, and conservative advice for women continues to be to avoid alcohol use during pregnancy.

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.