Duration of residence and offspring birth weight among foreign-born mothers in Spain: a cross-sectional study.

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.