Migration trajectories, uncertainty and health: a conceptual review

Migration trajectories are complex, non-linear movements, including periods of immobility, secondary migration, return and psychosocial changes. A defining feature of these trajectories is uncertainty, resulting from incomplete place-based knowledge and the unpredictable future. We examined how migration trajectories and associated uncertainties have been conceptualised and operationalised in health-related research.

We conducted a conceptual review with systematic searches in Medline, Embase, Web of Science, and Global Index Medicus. After duplicate screening, we extracted information on concept definitions, operationalisations and links to health. Uncertainty factors were categorised and mapped followed by a narrative synthesis (PROSPERO protocol: CRD42024579247).

From 3836 titles after deduplication, 66 were synthesised which used various designs and mostly focused on forced migrants in high-income countries. Concept definitions and operationalisations varied strongly. Phase models outlining consecutive migration stages were frequently applied, while sometimes also considering non-linearity of trajectories. Uncertainty was mostly mentioned regarding legal status, followed by uncertainty of the future, 'general' uncertainty of migration processes, and uncertainty of social relations. Fewer studies considered uncertainty of economic, healthcare, and societal factors. Uncertainties were mostly associated with adverse mental health.

The review illustrates a plethora of uncertainties along migration trajectories, with many studies showing negative psychological impacts of legal uncertainty. Current theorisations do, however, not tap the concept's potential to generate health-related knowledge across migration trajectories, particularly regarding mobility regimes, conceptual meanings and modal time. Avenues for further research include considering positive health outcomes, examining how mobility regimes affect 'possible futures', and enhancing methods for studying uncertainty.