The immigrant birthweight paradox in an urban cohort: Role of immigrant enclaves and ambient air pollution

Immigrants are a rapidly growing population in the United States (US). By the year 2065, immigrants and subsequent generations will account for 88% of the country’s growth or ~103 million people [1]. As such, research that investigates drivers of perinatal health outcomes among immigrants is critical for shaping the health of future generations.

Low birthweight is a leading cause of infant mortality and morbidity in the US and associated with learning, social, and motor developmental delays and chronic diseases later in life [2]. Approximately 8.2% of babies in the US are low birthweight (<2500 g) and 9.4% are preterm (<37 weeks) [2]. Racial/ethnic disparities in low birthweight are well-documented, with Black and Latina mothers having a higher risk of low birthweight children than White mothers [3]. However by nativity status, Latina and Black foreign-born mothers tend to have a lower risk than their US-born counterparts, on average, despite generally worse socioeconomic indicators (e.g., lower educational attainment, lower household income, limited-English proficiency) [4–8]. This phenomenon is often termed the “immigrant birthweight paradox” (IBP).