Migration and Low Birthweight: Testing Health Selection in Binational Data from Mexico and the U.S.

Erin R. Hamilton, University of California, Davis
Kate H. Choi, University of Western Ontario

Infants born to Mexican migrants have remarkably good health outcomes. This could result from the benefits that accrue to migrants or from the positive health selection of migrants. We arbitrate between these explanations using two sources of binational data. Using Mexican and U.S. vital statistics data, we confirmed that infants born to Mexican immigrants have a rate of low birthweight lower than infants born to U.S.-born mothers in all major race/ethnic groups and 34% lower than their counterparts born in Mexico, consistent with selection. We then determined that up to 26% of the selection ratio could be explained by geographic selection, or the fact that migrants originate from areas that are advantaged in terms of infant health. Next we will use birth history data from the Mexican Family Life Survey to test whether the difference between immigrants and non-migrants in Mexico arises from selection or benefits from migration.