Background: Growing evidence indicates that immigration policy and enforcement adversely affect the well-being of Latino immigrants, but fewer studies examine 'spillover effects' on USA-born Latinos. Immigration enforcement is often diffuse, covert and difficult to measure. By contrast, the federal immigration raid in Postville, Iowa, in 2008 was, at the time, the largest single-site federal immigration raid in US history. Methods: We employed a quasi-experimental design, examining ethnicity-specific patterns in birth outcomes before and after the Postville raid. We analysed Iowa birthcertificate data to compare risk of term and preterm low birthweight (LBW), by ethnicity and nativity, in the 37 weeks following the raid to the same 37-week period the previous year (n = 52 344). We model risk of adverse birth outcomes using modified Poisson regression and model distribution of birthweight using quantile regression. Results: Infants born to Latina mothers had a 24% greater risk of LBW after the raid when compared with the same period 1 year earlier [risk ratio (95% confidence interval) = 1.24 (0.98, 1.57)]. No such change was observed among infants born to non-Latina White mothers. Increased risk of LBW was observed for USA-born and immigrant Latina mothers. The association between raid timing and LBW was stronger among term than preterm births. Changes in birthweight after the raid primarily reflected decreased birthweight below the 5th percentile of the distribution, not a shift in mean birthweight. Conclusions: Our findings highlight the implications of racialized stressors not only for the health of Latino immigrants, but also for USA-born co-ethnics. © The Author 2017; all rights reserved.

Birth outcomes immigration enforcement Stress Nativity Latinos/Hispanics

educational status policy implementation regression analysis prenatal care Latina experimental design Caucasian demography second trimester pregnancy risk human wellbeing immigration Premature Birth Stress, Psychological mental stress priority journal health status ethnic group comparative study premature labor Logistic Models ethnology procedures Hispanic Americans Undocumented Immigrants United States Young Adult Humans undocumented immigrant ethnic difference racism Hispanic psychology Infant, Newborn male immigration policy female adverse outcome Infant newborn pregnancy Infant, Low Birth Weight birth certificate Article low birth weight pregnancy outcome mother adult European Continental Ancestry Group term birth prematurity Italy ethnicity statistical model Birth Certificates Birth Weight body mass third trimester pregnancy first trimester pregnancy Lazio Iowa law enforcement gestational age