Newborn birth weights and related factors of native and immigrant residents of Spain.

Birth weight is a high impact factor in populations with high rates of immigration. This study establishes differences in birth weight (BW) and related factors among full-term newborn (NB) infants born to native and immigrant women living in Spain during 2007-2008. All NBs from Spanish mothers and mothers from the five nationalities with the highest birth rates in Spain (Morocco, Romania, Ecuador, Bolivia, and Colombia) according to the Statistical Bulletin of Births in Spain were included. BW was classified as low BW (LBW; <2,500 g), underweight (UW; 2,500-2,999 g), adequate weight (3,000-3,999 g), and macrosomia (≥4,000 g). The characteristics associated with a higher likelihood of LBW were Spanish mother, lower training level (OR = 1.3), more children (OR = 1.8), age ≤19 years (OR = 1.2) or ≥40 years (OR = 1.3), and female NB. The probability of macrosomia was higher in Bolivian mothers (OR = 3.0) with more children (OR = 1.7) and male NBs (OR = 2.0). The NBs of Spanish mothers have a higher likelihood of LBW and the lowest odds for macrosomía compared with immigrants from the other countries.