mothers during pregnancy; children both pre-alcohol use around ages 7-10, and post-alcohol use around ages 13-23). Results The PRS were associated with multiple alcohol consumption phenotypes (strongest signal for alcohol amount at 18 weeks gestation: p=1.01×10 -5 ) in pregnant mothers. There was an effect of maternal PRS for alcohol use on mother's perinatal depression (p=0.02), offspring intellect (p=0.016), and ADHD (p=0.04). Discussion The effects of alcohol PRS previously found in the general population are also shown during pregnancy. We found an intrauterine effect of alcohol PRS on offspring intellect and ADHD. The effects shown are not due to offspring's own alcohol use, as these effects were not found within the child's analyses.