The Impact of Ethnicity and Migration on Pregnancy and Birth Outcomes: A Secondary Analysis of the Born in Bradford Cohort.

International evidence suggests differences in perinatal outcomes between migrant women and their native-born peers, but the intergeneration impact of family migration and interplay with maternal ethnicity remains unclear. This study investigates the relationships between maternal ethnicity, migration status, and perinatal outcomes using secondary analysis of data obtained by an established birth cohort study in the north of England using regression models. Pakistani migrants had higher odds of low birth weight and lower odds of macrosomia compared to white British natives. Pakistani migrants of all generations had higher odds of gestational diabetes, with odds among first-generation migrants almost double that of second-generation migrants. First-generation Pakistani migrants also had lower odds of preterm birth and Apgar score < 7 at 1 min in comparison with other groups. Lower incidence of premature birth in first-generation migrant Pakistani women is of importance. Higher odds of low birth weight and lower odds of macrosomia among Pakistani migrants compared to white British women merits further investigation. It is noteworthy that this is despite higher odds of gestational diabetes overall in this population and generational differences in among Pakistani migrants requiring further attention, with a full consideration of confounding environmental and biological factors, with a view to addressing identified inequalities.