Smoking, drinking excess alcohol, poor nutrition and other lifestyle factors can lead to poor outcomes for mothers and babies. The provision of routine health promotion (including advice and education and sometimes screening tests) before conception may encourage changes to improve health, and may be an opportunity to identify risk factors such as infection that can be treated before pregnancy begins. The review looks at randomised controlled trials examining routine health promotion before pregnancy to see whether it changes behaviour and leads to improved health for mothers and babies. Four trials with 2300 women provided information for the review. The health promotion offered to women in these studies ranged from very brief advice on a specific topic through to more general advice and education on health and lifestyle over several sessions. In only one study were women followed up through pregnancy and there was little evidence of any differences between groups, although the babies of women who had received the health promotion intervention had slightly lower birthweights. There was some evidence that health promotion interventions encourage women to have more healthy lifestyles, such as lower rates of binge drinking. Overall, there was little evidence on the effects of pre-pregnancy health promotion on the health of mothers and babies, and more evidence is needed before its widespread implementation can be recommended.