Objectives: The healthy immigrant effect is the phenomenon by which immigrants experience more positive health outcomes than the native-born population in developed countries. The strength of this effect appears to be related to country of origin, health outcome, healthcare and integration policies of receiving countries, as well as immigration class. This secondary analysis of birth records examines whether immigrants and mothers from refugee countries have lower adjusted risk of preterm births than US-born mothers in Syracuse, NY, a preferred refugee resettlement area.
Methods: This secondary analysis included 6354 electronic birth records for residents in the city of Syracuse, NY who gave birth to singleton infants between 2009 and 2011. Multivariate log-binomial regression was used to calculate the adjusted relative risk for preterm birth among foreign-born mothers and mothers from refugee countries, compared to US-born mothers.
Results: Infants born to both foreign-born women and to women from refugee countries had decreased risks of being born preterm compared to infants born to US mothers, controlling for race, late/no prenatal care, maternal age less than 18 years and smoking.
Conclusion: Our findings support a healthy immigrant effect for preterm births both among all foreign-born immigrants and among the subsample of women from refugee countries. Mother's nativity is likely a proxy for unmeasured factors (e.g., prenatal stress, maternal diet, etc.) that may explain the relationship between mother's nativity and preterm births. Additional research is needed to better understand the underlying factors.
Keywords: Foreign-born birth outcomes; Healthy immigrant effect; Immigrants and refugees; Preterm birth; Risk and protective factors for preterm birth.