Despite advances in health care, research shows that infant mortality rates in African-American communities have been approximately twice as high as the rates for whites in the United States for nearly a century. Because preterm births account for the vast majority of infant deaths, it is becoming increasingly clear that more research on the cause of this problem is needed if infant mortality rates for blacks are to decrease to the level of their white counterparts.

Significant research has already been undertaken to understand racial disparities in preterm birth. However, rather than focusing specifically on the black community the majority of studies have examined women from all ethnic backgrounds within the same study, with results averaged across the different racial cohorts, meaning the differences between these two distinct subject groups have not been considered. Leading the National Institutes of Health R01-funded research project, "The Impact of Racism on Risk of Preterm Birth in African-American Women," Dawn Misra, M.H.S., Ph.D., professor and associate chair for research in the Department of Family Medicine and Public Health Sciences in the School of Medicine at Wayne State University, points out that the gap persists even for black women who are more affluent and better educated.

Dr. Misra said a failure to "rigorously and comprehensively" include racism among the factors that contribute to this unbalanced trend has prevented real progress from taking place. "Whether racism is perceived internally by the individual, has become institutionalized or has led to segregation across entire communities, this exposure is believed to have a profound impact on the birth outcomes of black women," she said. "It has also been suggested that racism is related to several preterm birth risk factors, such as chronic disease and stress, and effects across generations may be the result of racism in the past. Only a small number of studies have explored the impact of racism on birth outcomes."

One of the biggest challenges for Dr. Misra and her team is convincing others of the need to carry out this research exclusively within the African-American community rather than comparing black and white subjects, as earlier studies have done. The main problem was obtaining funding, but once it was secured there was strong support from both the medical community and potential study subjects.

"This issue resonates strongly with the black community," Dr. Misra explained. "The women who took part were recruited from the community-based Providence Hospital so that the team could conduct interviews as well as examine medical records and existing databases. None of the work we have done would have been possible without the women who have been so generous and thoughtful in sharing their lives with us. These women have recognized the value of what we are endeavouring to accomplish."

The hospital's physicians, nurses and administrators were also supportive, and facilitated the research in a number of ways, she noted.

In the recently published paper led by Jaime C. Slaughter-Acey, Ph.D., a former postdoctoral fellow from Dr. Misra's team who is now on the faculty at Drexel University, the data from this study were used to examine the impact of racism in the form of micro-aggressions on the risk of preterm birth. Most studies examining the relationship between racism and birth outcomes have focused on the impact of major experiences of discrimination, rather than on micro-aggressions. Racial micro-aggressions are often encountered with greater frequency than major experiences, and produce an environment with an expectation that something racist will occur. Although a single event may not be perceived as serious, accumulation of these seemingly innocuous events on a weekly or even daily basis over the course of one's life may more readily overtax an individual's stress response systems than major experiences of racial discrimination. Beyond the measurement of interpersonal racism or racial discrimination, the variation in associations with birth outcomes could be due to underlying effect modification. Research suggests that other psychosocial risk factors may moderate the relationship between racism and preterm birth such that the impact may only be expressed in the presence or absence of these other psychosocial factors.

In the new Annals of Epidemiology paper by Slaughter-Acey et. al., "Racism in the form of micro-aggressions and the risk of preterm birth among black women," one dimension of racism was measured by the Daily Life Experiences-Bother (DLE-B) scale, which captures the frequency and perceived stressfulness of racial micro-aggressions in the past year as reported by mothers in the immediate postpartum period. This measure of racism was significantly associated with the rate of preterm birth among black women with mild to moderate depressive symptoms, but was not associated for those with severe depressive symptoms. This suggests that racism may not further impact a group already at high risk for preterm birth, such as those experiencing severe depression symptomology, but may increase the risk of preterm birth for women at lower baseline risk. The results suggest that research on the intersection of racism and psychosocial factors such as depressive symptomology may provide additional insight into the complex and persistent racial disparities in birth outcomes.

While preterm birth rates have fallen for white and black women over the years, rates among black women remain much higher than for whites.

"If we are to eliminate the persistent racial disparity in this birth outcome, it is imperative that upstream social risk factors that are amenable to effective intervention be identified," Dr. Misra said. "Overcoming these impediments will require bold and innovative changes in society, as well as the public health and medical care arenas. We view our work as a contribution to an ever-evolving set of ideas."

The study was funded by the National Institutes of Health, grant number R01HD058510. Co-investigators include Cleo Caldwell, Ph.D., University of Michigan; Theresa Osypuk, Ph.D., Northeastern University; and Dr. Robert Platt, Ph.D., McGill University. Other team members include: Jennifer Straughen, Ph.D., WSU postdoctoral student, now assistant scientist for Henry Ford Health System; Jaime Slaughter-Acey, Ph.D., postdoctoral student and first author of this paper, now assistant professor at Drexel University; Carmen Giurgescu, Ph.D., assistant professor, Wayne State University College of Nursing; Dr. Shawnita Sealy-Jefferson, Ph.D., M.P.H., postdoctoral student and now assistant professor, Virginia Commonwealth University; and Rhonda Dailey, M.D., WSU research associate.