A study was set up to compare the drinking habits of women of childbearing age in two cities (Milan and Southampton) in two countries, Italy and the United Kingdom, and to look at the effects of alcohol consumption on the weight of the babies born to these women. The sample consisted of 1516 women in Milan and 996 in Southampton, who were interviewed after delivery; data on their drinking history, before and during pregnancy, were gathered, together with social, demographic and health data. The clinical records of the women and their babies were examined. On average, both groups drank less than one unit/day before pregnancy, but there were differences in drinking habits between the two countries, as well as in the modifications induced by pregnancy. The possible effects of alcohol on birthweight were then considered. After controlling for confounding factors, there was no general association between birthweight and alcohol consumption. The impact on health education policy is discussed.