Sebastian Tello-Trillo is an assistant professor of public policy and economics at the Batten School of Public Policy at the University of Virginia. His research focuses on health policy in the U.S. and Latin America.

Immigration policy and health policy are often seen as completely separate, with one rarely coming up when we talk about the other. But we have numerous studies showing how the threat of deportation or job loss from immigration enforcement can negatively impact people’s physical and mental health, including their likelihood of accessing coverage and COVID-19 vaccination. What we haven’t had — until now — is research on the consequences for babies born into a world with aggressive immigration enforcement.

In a new paper soon to be published in the American Journal of Health Economics, researchers Catalina Amuedo-Dorantes, Brandyn Churchill and Yang Song looked at whether the unprecedented increase in immigration enforcement between 2003 and 2016 (leading to more than 3.6 million undocumented immigrants being deported) was associated with lower birth weights of babies born to likely undocumented parents. Previous research has shown major traumatic events like hurricanes and wars can lead to a reduction in birth weight (which is associated with increased infant mortality and worse health later in life), but this is the first study to look at the impact of immigration enforcement.

The authors created an index that captured the intensity of immigration enforcement in every county in the U.S. based on federal, state and local policies and compared infant birth weights in counties with differing levels of immigration enforcement. (Because undocumented status wasn’t available in their data, they used other characteristics — ethnicity, education level and country of origin — to find mothers likely to be undocumented.)

The researchers found that when a county adds one more immigration enforcement policy during the third trimester of a likely undocumented mother, the likelihood of her having a low-birth weight baby increases by 6%. The authors were unable to definitively pinpoint what specifically about immigration enforcement is associated with lower birth weights, but less health care access and more maternal stress could be part of the story. There are a number of limitations with this study. For example, the authors can’t know for sure the mothers’ immigration statuses or whether they actually experienced immigration enforcement during their pregnancies. 

So often we read heart-breaking stories about the negative health effects families experience because of fear and stress caused by our immigration policies. Thanks to studies like this one, we can begin to understand the systematic and long-lasting harms these policies have too.