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How Immigration Raids Lead to Lower Birth Weights

Researchers investigate the strange aftermath of the Postville raid.

By Nathan Collins


The slaughterhouse and meat packing plant in Postville, Iowa, the site of the raid. (Photo: Wikimedia Commons)

In the midst of one of the more vigorous debates in recent memory, here’s a reminder that immigration is not just a matter of the economy, crime, or the perceived threat of terrorism: According to a new study, raids targeted at undocumented immigrants may lower birth weight.

That’s not as bizarre a claim as it might at first sound. Though the reasons aren’t entirely clear, stress has been linked to low birth weight. In a study published last year, for example, public-health researchers linked low birth weight to socioeconomic status, particularly in the United States, hinting that stresses associated with poverty and discrimination could affect fetal development. A 2012 review similarly concluded that, among other sources of stress and anxiety, “exposure to racism [is] associated with lower birth weight with consequences for infant development.”

Research also shows that it’s stressful to be an undocumented immigrant. A 2013 review found that immigration policies limited access to health care, which was linked to higher rates of mental-health problems including depression, anxiety, and post-traumatic stress disorder.

With all that in mind, University of Michigan public-health researchers Nicole Novak, Arline Geronimus, and Aresha Martinez-Cardoso decided to focus on the effects of one particular—and particularly stressful—event, a 2008 raid on a slaughterhouse and meat-packing plant in Postville, Iowa. That raid, which involved 900 Immigration and Customs Enforcement officers and a Black Hawk helicopter, put a 10th of the small town’s population in jail and kept about half of its students out of school the following day, the Washington Post reported. Almost everyone affected was Latino.

The question is, what did the Postville raid do to children born around that time? Novak, Geronimus, and Martinez-Cardoso gathered birth certificates for all infants born to Latina mothers in the 37 weeks after the raid, and those born in the corresponding window one and two years earlier, then compared birth weights.

After controlling for mothers’ ages at the time of birth, the babies’ sexes, and an estimate of the child’s gestational age, among other factors, the researchers found that there was a small uptick in the number of low-birth-weight infants, defined as those weighing less than 2.5 kilograms or about five-and-a-half pounds, after the raid. For instance, the rate of low birth weight among foreign-born Latina mothers after the raid was around 6 percent, compared to 4 or 5 percent at the same time of year in 2006 and 2007.

Interestingly, rates of low birth weight went up for children of U.S.-born Latinas as well, the researchers found, but not for other white mothers, suggesting the effects extended beyond those who would have been most directly affected by the raid.

“The Postville raid was an extreme example of diffuse and pervasive racialized economic and psychosocial stressors that Latinos face throughout the USA,” the researchers write in the International Journal of Epidemiology. “Exclusive immigration policies and their militarized enforcement exacerbate the racialized exclusion of Latinos in the USA, which may contribute to a cumulative health burden for immigrant and USA-born Latinos alike.”