Background: Although it has long been acknowledged that chronic HPA axis dysregulation impacts on adult neural function, little attention has been paid to the impact that disturbances of the maternal HPA axis may have on the developing fetal brain. Aim: This editorial examines the associations between prenatal stress, neuroendocrine functioning, and behavioural. outcome in both animal and human offspring, with a particular focus on the relationship between prenatal stress and human fetal and infant neurobehaviour. Study design: Using electronic databases, a computerized search of published and unpublished data was undertaken. Results: There is growing evidence that prenatal stress impacts on offspring neural function and behaviour in animal populations. That these findings may be applicable to human fetal neurobehaviour and infant development and outcome is gaining research attention, and the potential importance of the timing of pregnancy stress is being increasingly highlighted. Conclusions: There is a pressing need for more research into the role of maternal stress and anxiety during pregnancy on human fetal and infant outcomes. Future studies should prospectively pair physiological and psychological measures both pre- and postnatally if the HPA axis function of the mother and her infant is to be more fully understood. (c) 2005 Elsevier Ireland Ltd. All rights reserved.