Deaths across borders: Trends and challenges in estimating mortality among undocumented migrants on Latin American routes.

Introduction: Undocumented migrants in Latin America face life-threatening conditions during irregular border crossings, yet their mortality remains under-documented and structurally invisible in public health research. This study analyzes migrant deaths and assesses the methodological limitations in estimating mortality for those populations.

Methods: Cross-sectional data were drawn from the Missing Migrants Project, covering deaths and disappearances of Latin American migrants within the region from 2014 to 2022. The final sample included 1,817 documented fatalities with complete data on year and origin. The study analyzed spatial and temporal trends by region, migration route, country of origin, and cause of death. Data were grouped into three periods and tested for distributional differences using chi-square tests.

Results: From 1,817 deaths, nearly half occurred between 2020 and 2022. Regional patterns shifted over time, with a rising share of deaths in South America, particularly along the Darién Gap. Venezuelan and Haitian migrants accounted for the largest increases in deaths in recent years. Causes varied by route: drowning predominated in maritime crossings, while environmental exposure and violence were prevalent in jungle and borderland routes. Documentation improved over time, yet a large share of deaths remained unattributed to specific routes or causes.

Conclusions: Undocumented migrant mortality in Latin America is shaped by structural violence, fragile transit infrastructures, and inadequate data systems. Conventional demographic tools fail to capture these patterns due to missing denominators and fluid migration flows. Addressing these deaths requires new frameworks grounded in human rights, improved data systems, and expanded access to safe migration pathways.