Alcohol crosses the placenta and is potentially teratogenic. The most severe consequence is foetal alcohol syndrome (incidence 1:1000 live births) which describes a characteristic range of physical and neurodevelopmental anomalies. Milder or more focal abnormalities are collectively described as Foetal Alcohol Spectrum Disorder (incidence up to 9:1000 live births). The financial consequences of foetal alcohol syndrome are also considerable.Prevention strategies include public health programmes and measures targeted at pregnant women. All pregnant women should be screened for level of alcohol consumption and those at increased risk offered targeted intervention. Current RCOG advice to pregnant women is to avoid alcohol in the first 12 weeks, and thereafter drink no more than 1–2 units once or twice a week. Binge drinking is particularly harmful. Further research is needed to establish the best interventions, the safe limit (if any) of alcohol intake, and to improve the diagnosis of foetal alcohol spectrum disorder.