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While there has been considerable public discussion regarding how to improve maternity leave and the care of mothers and infants following birth, there has been far less attention paid to prenatal care.

A study I co-authored recently illustrates why it’s time for that to change.

The study, published in Economics & Human Biology, found that pregnant women who commute 50 miles or more to work each way are at increased risk of adverse birth outcomes, including having babies born at low birth-weight. 

Working with my colleague Yang Wang, associate professor of public affairs at the University of Wisconsin-Madison, our analysis concluded that increased maternal stress and underutilization of prenatal care are the most likely explanations for the adverse birth outcomes we saw in the data.

Our study reveals a vicious self-reinforcing cycle: The chronic strain caused by a long commute—an average of 64 miles each way for the pregnant women in our study sample—increases the risk of maternal stress. That, in turn, creates a greater need for prenatal care. But the long commute leaves those pregnant women with less time to schedule prenatal doctor visits and practice better self-care.

Increased Risk of Low Birth-Weight Babies

Here’s a closer look at our findings:

We analyzed data from New Jersey birth records for the years 2014 and 2015, which is when the state began collecting information on the address of a mother’s employer, as well as her home address. That allowed us to calculate how far the pregnant women were commuting to work.

We were then able to correlate commuting distance against adverse birth outcomes listed on the birth records.

For pregnant women with a long commute, defined as traveling 50 miles or more to work each way, we found that each 10-mile increase in travel distance raises the probability of low birth weight by 0.9 percentage points—or 14 percent, compared to the national average.

So the longer the commute, the higher the risk of a low birth-weight baby (defined as weighing less than 5 pounds, 8 ounces).

We also discovered that each 10-mile increase in travel distance for pregnant women with a long commute raises the probability of intrauterine growth restriction (when a fetus is smaller than expected for the number of weeks of pregnancy) by 0.6 percentage points.

Negative Impact on Prenatal Care

Previous studies have shown a correlation between birth outcomes and the distance from a pregnant woman’s home to her health care provider. And it certainly makes sense that if a mother lives farther from her health care provider, it could have a negative impact on her prenatal care.

Our study marks the first research on the effects of long commutes during pregnancy on infant health. In addition to our findings on adverse birth outcomes, maternal stress has previously been linked to increased risk of male babies being delivered by cesarean section, or c-section. And we did find a correlation in the data between male babies delivered by c-section and long commutes, which provides further evidence of the likely role of maternal stress in birth outcomes for women with long commutes.

While we went into the study expecting to find a link between long commutes and maternal stress, we did not expect to find a connection to underutilization of prenatal care.

But we did. Once again, each 10-mile increase in travel distance for pregnant women with long commutes was linked to a 2.5 percent reduction in total prenatal visits and a 2.84 percent decrease in the probability that they would have their crucial first prenatal visit early in their pregnancy, during their first trimester. 

The correlation between long commutes and waiting longer than recommended to schedule a first prenatal visit, plus having fewer prenatal visits over the course of pregnancy, should be part of our public discussion on adopting more family-friendly policies.

The United States ranks last among 41 highly industrialized countries in every measure of family-friendly policies, including guaranteed paid leave for mothers and fathers, according to a report released earlier this year by UNICEF.

Our study highlights that finding ways to expand maternity leave to cover the prenatal period should be part of future public policy discussions. 

Muzhe Yang

Muzhe Yang

Muzhe Yang, Ph.D. is an associate professor in the Department of Economics at Lehigh Business.