In a study published in Economics & Human Biology, researchers from Lehigh University and the University of Wisconsin-Madison found that pregnant women who commute long-distance to work have an increased risk of adverse birth outcomes, including having babies born at a low-birth weight. The study is the first to examine the impact of long-distance commuting during pregnancy on infant health.
An analysis of data gleaned from 2014 and 2015 New Jersey birth records revealed that for pregnant women who commute at least 50 miles to work, each 10 miles of travel distance increased the probability of having a low-birth-weight baby by nearly one percentage point (0.9) or 14 percent, compared to the national average. In other words, the longer the long-distance commute, the higher the risk for giving birth to a low-birth-weight infant. Low birth weight is defined as under 2,500 grams―or about 5.5 pounds.
Increasing maternal travel distance by ten miles―over the 50-mile long-distance threshold―was also associated with an increase in the probability of slowed fetal growth, known as intrauterine growth restriction. For every ten miles or travel distance added to a long commute, the probability of having intrauterine growth restriction increased by 0.6 percentage points or 43 percent, compared to the average rate among pregnant women living within 10 miles of their workplaces.