Perinatal health outcomes of international migrant women in Brazil: A nationwide data linkage study of the CIDACS birth cohort (2011–2018)

Background: We investigated perinatal outcomes among live births from international migrant and local-born mothers in a cohort of low-income individuals in Brazil. Methods: We linked nationwide birth registries to mortality records and socioeconomic data from the CIDACS Birth Cohort and studied singleton live births of women aged 10–49 years from 1st January 2011 to 31st December 2018. We used logistic regressions to investigate differences in antenatal care, adverse pregnancy outcomes, and neonatal (i.e., ≤28 days) mortality among international migrants compared to non-migrants in Brazil; and explored the interaction between migration, race/ethnicity and living in international border municipalities. Results: We studied 10,279,011 live births, of which 9469 (0.1 %) were born to international migrants. Migrant women were more likely than their Brazilian-born counterparts to have a previous foetal loss (ORadj: 1.16, 1.11–1.22), a delayed start of antenatal care (i.e., beyond 1st trimester) (1.22, 95%CI:1.16–1.28), a newborn who is large for gestational age (1.29, 1.22–1.36), or a newborn with congenital anomalies (1.37, 1.14–1.65). Conversely, migrant women were less likely to deliver prematurely (0.89, 0.82–0.95) or have a low birth weight infant (0.74, 0.68–0.81). There were no differences in neonatal mortality rates between migrants and non-migrants. Our analyses also showed that, when disparities in perinatal outcomes were present, disparities were mostly concentrated among indigenous mothers in international borders and among live births of Black mothers in non-borders. Conclusion: Although live births of international migrants generally have lower rates of adverse birth outcomes, our results suggest that indigenous and Black migrant mothers may face disproportionate barriers to accessing antenatal care