Abstract
BACKGROUND: Duration of residence has been used to monitor changes in the health of a foreign-born population in a destination country. This study assesses whether the mother's duration of residence influences the relationship between maternal origin and birth weight. METHODS: We conducted a cross-sectional study using Spanish census microdata (2011) linked to Vital Statistics (2011-15). Linear and multinomial logistic regression models were used to estimate birth weight differences between children born to foreign-born mothers by duration of residence and those born to natives. Maternal countries of origin were classified according to the Human Development Index (HDI). RESULTS: Our findings revealed significant differences in birth weight of 109 683 births from both foreign- and native-born mothers. Overall, in descriptive statistics, compared with Spanish mothers, foreign-born mothers gave birth more frequently to high-birth weight (HBW) newborns (8.4% vs. 5.3%, respectively) and less frequently to low-birth weight (LBW) newborns (4.8% vs. 5.1%). According to the model's estimations, the risk of giving birth to HBW babies remains relatively high in foreign-born mothers. Especially, mothers from very high-HDI countries experienced changes in the RRR of HBW (1.59-1.28) and LBW (0.58-0.89) after spending over 10 years in Spain. CONCLUSIONS: Foreign-born mothers residing in Spain are at increased risk of delivering a HBW child regardless of their duration of residence. In fact, given the long-term health consequences associated with HBW, our results highlight the need to improve prenatal care in the foreign-born population.