RESUMO
BACKGROUND: Midwifery continuity of carer (MCoC) is a model of care in which the same midwife or small team of midwives supports women throughout pregnancy, birth and the postnatal period. The model has been prioritised by policy makers in a number of high-income countries, but widespread implementation and sustainability has proved challenging. METHODS: In this narrative review and synthesis of the global literature on the implementation and sustainability of midwifery continuity of carer, we identify barriers to, and facilitators of, this model of delivering maternity care. By mapping existing research evidence onto the Consolidated Framework for Implementation Research (CFIR), we identify factors for organisations to consider when planning and implementing midwifery continuity of carer as well as gaps in the current research evidence. RESULTS: Analysing international evidence using the CFIR shows that evidence around midwifery continuity of carer implementation is patchy and fragmented, and that the impetus for change is not critically examined. Existing literature pays insufficient attention to core aspects of the innovation such as the centrality of on call working arrangements and alignment with the professional values of midwifery. There is also limited attention to the political and structural contexts into which midwifery continuity of carer is introduced. CONCLUSIONS: By synthesizing international research evidence with the CFIR, we identify factors for organisations to consider when planning and implementing midwifery continuity of carer. We also call for more systematic and contextual evidence to aid understanding of the implementation or non-implementation of midwifery continuity of carer. Existing evidence should be critically evaluated and used more cautiously in support of claims about the model of care and its implementation, especially when implementation is occurring in different settings and contexts to the research being cited.