Immigrant apprehensions and birth outcomes: Evidence from California birth records 2008-2015.

While several studies find adverse birth outcomes among Latina mothers after discrete immigration enforcement events, it is unknown whether day-to-day enforcement activities precede adverse birth outcomes. This study examines birth outcomes among Latinas following local immigrant apprehensions-48-h holds on suspected undocumented immigrants by local law enforcement-over an 8-year period. County-level apprehensions, scaled to 1000 of the population, were averaged across the third trimester. We analyzed the association between county-level apprehensions and low birth weight (LBW) and preterm birth (PTB) between 2008 and 2015 in California using spline logistic regression models with knots at the quartiles of apprehensions and included covariates, county fixed-effects, and a time propensity variable to account for trend and seasonality in LBW and PTB. We performed these regressions for non-Hispanic White, all Latina, and foreign-born (FB) Latina mothers. There were no significant associations between apprehensions and LBW. For all Latina women, there were no differences in PTB between zero apprehensions and levels that were below the median. Latina mothers exposed to moderately high apprehensions had lower odds for PTB compared to zero apprehensions. At the highest levels of apprehensions, however, Latina women showed significantly elevated odds of PTB (at 0.71 apprehensions: OR = 1.06, 95% CI 1.01-1.12). PTB responded differentially to localized enforcement threats. At lower and moderate levels, Latino communities may have mobilized in ways that reduced the risk for PTB. Risks emerged at the highest levels of enforcement, underlying the intense fear and anxiety in hyper-surveilled areas.