Last week, the March of Dimes issued a report card for the United States preterm birth rate. The U.S. got a “D.”

More than 540,000 babies are born too early. A baby is considered “pre-term” if it is born before 37 weeks. According to the Institute of Medicine, preterm births and complications (breathing problems, cerebral palsy, mental retardation) account for health care expenses in excess of $26 billion a year.

African-American women at every socioeconomic level have higher rates of preterm birth and infant mortality. Incredibly, these rates exceed those of white women who have not even finished high school and those of black women who emigrated to the U.S. from other countries. For example, infant mortality in white women with a college degree or higher is 4 per 1000, while for similarly educated African-American women, the rate is 12 per 1000 births. Infant mortality is too high in both of these groups. It is shameful that the U.S. infant mortality rate is one of the highest in the industrialized world.

Why has this disparity persisted in African-American women? The answer may surprise you, but maybe not.

Being black in America is bad for a woman’s health. Why? Chronic racism over the lifetime of African-American women affects their birth outcomes. Not just living in poverty, the frequency of prenatal visits (still important), level of education or income. In the acclaimed documentary, “Unnatural Causes,” a critical examination of health care disparities in the U.S., Dr. Richard Davis states, “There’s something about growing up as a black female in the United States that’s not good for your childbearing health.”

True words.

Researchers have found physiologic pathways may increase the risk of premature infants. One way is related to a hyperactivation of the neuroendocrine system (related to pregnancy) and the second is an immune/inflammatory pathway. Maternal stress increases both. The exposure of stress to chronic racism has been listed as a very possible and plausible risk factor in African-American women.

Also, there is another notion that may explain worse outcomes. “The “weathering” hypothesis was first described by Dr. Arline Geronimus to explain how the poor health consequences and potential health deterioration that African-American women experience is secondary to the cumulative impact of repeated experiences with social or economic adversity or political marginalization. Dr. Camara Jones, who is also seen on the documentary, says that the chronic stress of racism is like “gunning the engine of a car, never letting up.” The bottom line…we cannot continue to explain away health care disparities because of socio-economic status or poverty.

Historically, the medical community has downplayed the long-term medical effects of chronic racism, because of its subjective nature, and because of an inability to accurately measure its occurrence. Since the 1990s, the relationship between maternal chronic stress and pregnancy outcomes have been studied with documented associations. Advances in stress markers and the ability to measure them can give health care providers concrete assessments to address and measure stress circumstances in expectant African-American women.

Clearly, African-American women can’t go back in time to eliminate past exposures to racism or perceived racism. Thankfully, every woman exposed to chronic stress does not deliver a preterm infant.

If you are pregnant, take steps now to monitor stress in your life. Establish the causes of the stressors and focus on healthy coping responses. Know what situations are in your control what situations are out of your control. Eliminate unhealthy relationships, people or ideas that do not make you better. Learn to say “No,” and mean it. We need healthy mothers and healthy families.

African-American women can ‘weather’ chronic stress from racism – by supporting each other, understanding where our strength comes from, and using faith and spirituality to honor our health and ourselves.