Infant birth weight in Brazil: A cross-sectional historical approach

In 1888, Brazil became the last country in the Americas to abolish slavery. Historians have outlined the racialized health disparities of people of African descent in the post-abolition period. Epidemiologists have shown that twenty-first-century health disparities continue to mirror patterns from over a century ago. This cross-sectional analysis quantifies health disparities in a post-abolition maternity hospital using infant birth weight. It relies on hospital records on infants delivered between 1922 and 1926 (n = 2845) at the Maternidade Laranjeiras in the city of Rio de Janeiro, Brazil to run linear models assessing differences in infant birth weight by maternal skin color, age, number of pregnancies (parity), and nationality. African ancestry was correlated with lower birth weights. Infants born to Afro-descendant women had birth weights estimated to be 84 g lighter (p-value = 0.002 [95% CI -137, -32]) than infants born to Euro-descendant women. Among Afro-descendant women, infants born to Black (preta) women had birth weights estimated to be 100 g lighter (p-value = 0.001 [95% CI -160, -39]) and infants born to mixed-race (parda) women had birth weights estimated to be 70 g lighter (p-value = 0.022 [95% CI -130, -10]) than infants born to White women. The findings were likely the consequence of slavery's legacy, particularly race-based socioeconomic inequality - including more strenuous work schedules, poorer nutrition, and less sanitary living environments for people of African descent. The findings are consistent with current-day research on racialized health disparities in Brazil and demonstrate the importance of historical findings to public health research.