Adverse birth outcomes among native-born and immigrant women: replicating national evidence regarding Mexicans at the local level.

For almost two decades, the literature has consistently described an epidemiologic paradox relating to better birth outcomes among high-risk groups, particularly new immigrants from Mexico and Southeast Asia. We hypothesize that regardless of their sociodemographic profile, Mexican immigrants will exhibit lower rates of low birth weight and preterm deliveries than native-(U.S.) born women of Mexican origin, non-Hispanic White and Black women, and Puerto Rican Women. We studied 57,324 live-born singleton infants born to residents in the city of Chicago in a linked data set of 1994 birth-death records. Multivariate logistic regression was used to analyze race/ethnicity differentials in two pregnancy outcome measures, low birth weight and preterm birth. Overall better birth outcome is related to maternal immigrant status regardless of race/ethnic groups. Immigrant Mexican women had a significantly lower risk of both low birth weight [adjusted odds ratio (AOR): 0.78, 95% confidence interval (CI) 0.66-0.91] and preterm births (AOR: 0.75, 95% CI 0.65-0.86) and were at 28% and 33% lower risks of delivering a low birth weight infant or a premature infant, respectively, than non-Hispanic White women.