Differing first year mortality rates of term births to white, African-American, and Mexican-American US-born and foreign-born mothers

To determine whether maternal nativity (US-born versus foreign-born) is associated with the first year mortality rates of term births. Stratified and multivariable binomial regression analyses were performed on the 2003-2004 National Center for Health Statistics linked live birth-infant death cohort files. Only term (37-42 weeks) infants with non-Latina White, African-American, and Mexican-American mothers were studied. The infant mortality rate (<365 days, IMR) of births to US-born non-Latina White mothers (n = 3,684,569) exceeded that of births to foreignborn White mothers (n = 226,621): 2.4/1,000 versus 1.3/1,000, respectively; relative risk (RR) = 1.8 [95 %confidence interval (CI) 1.6-2.0]. The IMR of births to US-born African-American mothers (n = 787,452) exceeded that of births to foreign-born African-American mothers (n = 118,246): 4.1/1,000 versus 2.2/1,000, respectively; RR = 1.8 (1.6-2.1). The IMR of births to US-born Mexican-American mothers (n = 338,337) exceeded that of births to Mexican-born mothers (n = 719,837): 2.4/1,000 versus 1.8/1,000, respectively; RR = 1.3 (1.2-1.4). These disparities were not limited to a singular cause of death and were widest among deaths due to Sudden Infant Death Syndrome. In multivariable binomial regression models, the adjusted RR of infant mortality for non-LBW, term births to US-born (compared to foreign-born) for White, African-American, and Mexican-American mothers equaled 1.5 (1.3-1.7), 1.7 (1.5-2.1) and 1.6 (1.4-1.8), respectively. The IMR of term births to White, African-American, and Mexican-American mothers exceeds that of their counterparts with foreign-born mothers independent of traditional individual level risk factors.