Objectives: To consider how 'continuity of carer' has been defined in the literature and to review the literature on what aspects of continuity matter to women. Design: Structured literature review. Setting: The first objective was addressed within the context of a review of the organisation of midwifery services in the UK; for the second objective a wider literature was drawn on. Measurements and findings: Data were systematically extracted from the identified 'core' studies on the methods used for assessing continuity of carer and on women's satisfaction with periods of care. Continuity of carer was found to be defined in these studies as fewer caregivers, either overall or during pregnancy, or as a known caregiver in labour. Little attention was paid to other possible interpretations of continuity of carer. The literature on what is important to women was found to have used four distinct methods and findings were consistent within methods. Studies comparing women who had and had not had a known carer in labour found no significant differences in satisfaction; those using rankings or ratings found that a known intrapartum carer was a relatively low priority and most of those using open-ended questions found that few women mentioned continuity. In contrast, all studies which asked postnatal women whether a known intrapartum carer was important reported that those who had experienced it said 'yes', while those who had not, generally thought it unimportant. Key conclusions: There has been an emphasis in existing literature on continuity of carer but little attempt to assess continuity or quality of care. Limited definitions of continuity of carer have been used. There is no evidence that women who were cared for in labour by a midwife that they had already met were more satisfied than those who were not. Other aspects of woman-centred care were likely to be more important. Women wanted consistent care from caregivers that they trust, but most did not value continuity of carer for its own sake. Implications for practice: Limited definitions of continuity of carer seem to be becoming ends in themselves. This has particularly been the case with defining continuity as 'having a known carer in labour'. The available evidence does not justify prioritising this definition of continuity - rather the reverse. This is important for both women and midwives since it opens up other possibilities for organising services that put less strain on midwives' lives and may be equally satisfying for both women and midwives.