Pre-existing factors in mothers’ lives—such as hypertension, obesity, smoking, diabetes, drug use, alcohol use, poor maternal health and lack of antenatal care—are contributing to an unsettling disparity in birth outcomes based on race, according to surveillance conducted by the Centers for Disease Control and Prevention (CDC) and reported by National Public Radio (NPR).

The report showed that black women across the United States face worse birth outcomes than white or Hispanic women. What’s more, data confirmed that African-American infants are about 230 percent more likely than white infants to die before their first birthdays and black women are about 60 percent more likely than white women to deliver babies early.

Since birth outcomes often depend heavily on the health of mothers, neonatal health experts offered one possible explanation for this race-connected reproductive health disparity: the enormous stress experienced by women in low-income minority communities.

This stress is a result of working, raising children, taking care of ailing parents and dealing with material hardship, and it can deteriorate bodily systems—the cardiovascular system, the metabolic system and the immune system—explained Arline Geronimus, ScD, a professor at the University of Michigan’s School of Public Health.

“[African-American women of childbearing age are] suffering from hypertension at two or three times the rate of whites their own age,” Geronimus said. “We haven’t seen much traction over 20 to 30 years of trying to reduce and eliminate these disparities.”

Geronimus used the term “weathering” to refer to the compounding health problems black women faced as a result of stress. But, she added, impoverished black women weren’t the only ones at risk of this fate—so were their middle- and upper-class counterparts. Why? Because, in general, middle- and upper-class black people are under constant pressure to prove themselves, and to do so in environments where they may be the only black person present.

The good news is something is being done to help alleviate the stress on black moms’ health. Some states with high infant mortality rates, such as Delaware, are devoting more resources to mothers’ health beyond standard medical care.

But what would help even more, researchers said, is for states to understand how much government policies and urban planning can help close the gap in birth outcomes for African-American mothers.

Click here to read the NPR article, and click here for news about black infant mortality rates.