Migration and severe maternal outcomes in high income countries: systematic review and meta-analysis

BACKGROUND: Literature focusing on migration and maternal health inequalities is inconclusive. This is potentially explained by heterogeneous definitions and settings. Our objective was to assess migrants’ risk of severe maternal outcomes compared to native women in high income countries overall, according to host country, and by the migrant's region of birth. METHODS: Systematic literature review and meta-analysis using MEDLINE/Pubmed and EMBASE databases between 1990 and 25 March, 2022. Observational studies comparing the risk of maternal mortality or all-cause or cause-specific severe maternal morbidity in high income countries between migrant, defined by birth outside the host country, and native women, were included. Case-control and case studies were excluded. We performed random-effects meta-analyses when possible. Subgroup analyses were planned by host country and migrant's region of birth. RESULTS: From 2010 unique references, 36 studies reporting data from 32 databases were included. In Europe, migrants had a higher risk of maternal mortality than native women (RR 1.4;95%CI 1.1-1.6), but not in USA and Australia. Migrants born in sub-Saharan Africa (RR 3.3;95%CI 2.5-4.4), Latin America and the Caribbean (RR 2.8;95%CI 1.2-6.9), and Asia (RR 1.8;95%CI 1.3-2.4) were at higher risk of maternal mortality than natives, but not those born in Europe or the Middle East and North Africa. Patterns were similar for all-cause severe maternal morbidity. CONCLUSIONS: The differential risk of severe maternal outcomes in migrant versus native women in high income countries varies by host country and by women's region of origin. Our findings provide insight into the mechanisms of these inequalities. KEY MESSAGES: • In high income countries, the differential risk of severe maternal outcomes in migrants (born outside the host country) compared to natives, varies by the host country and the region of birth. • Our findings strengthens the evidence supporting the need to fight migrant’s health inequalities and to customise related health policies in each context.