Pregnancy is a 'window of opportunity' for encouraging positive behaviour change, such as quitting smoking. Associations have been shown between smoking stage of change and other health behaviour during pregnancy. For example, women in the precontemplative stage have poorer assessment of risks associated with smoking, feel less personally responsible for their unborn child's health and in turn are less likely to adopt health-promoting behaviour. Stage of change models are a popular tool within the health services, but the results of stage-based smoking cessation interventions are mixed. Identifying the crucial components of effective interventions is an important imperative for research in this area. This article reviews the literature to ascertain these components and makes recommendations for designing effective interventions.