Neighborhood Context and the Nativity Advantage in Preterm Birth among Black Women in California, USA.

Non-Hispanic Black women remain at increased risk for adverse birth outcomes, yet Black immigrant women are at lower risk than their US-born counterparts. This study examines whether neighborhood context contributes to the nativity advantage in preterm birth (PTB, < 37 weeks) among Black women in California. A sample of live singleton births to non-Hispanic US-born (n = 83,169), African-born (n = 7151), and Caribbean-born (n = 943) Black women was drawn from 2007 to 2010 California birth records and geocoded to urban census tracts. We used 2010 American Community Survey data to measure tract-level Black immigrant density, Black racial concentration, and a neighborhood deprivation index. Risk ratios (RR) and 95% confidence intervals (95%CI) were estimated using log-binomial regression to assess whether neighborhood context partially explained nativity differences in PTB risk. Compared to US-born Black women, African-born Black women had lower PTB risk (RR = 0.65, 95%CI: 0.60-0.71). The difference in PTB risk between US- and Caribbean-born women did not reach statistical significance (RR = 0.87, 95%CI: 0.71-1.05). The nativity advantage in PTB risk was robust to neighborhood social conditions and maternal factors for African-born women (RR = 0.59, 95%CI: 0.51-0.67). This study is one of few that considers area-level explanations of the nativity advantage among Black immigrants and makes a significant contribution by showing that the neighborhood context does not explain the nativity advantage in PTB among Black women in California. This could be due to many factors that should be examined in future research.