likely to deliver a low birth weight infant than those who had not experienced racism. This relationship was reduced by including preterm birth in the model, suggesting that the effect of discrimination on birth weight was as a result of the effects of racism on the likelihood of an earlier delivery. Thus, lifetime experiences of racism explained the racial and ethnic disparities in the rates of both preterm birth and low birth weight.
Collins and colleagues (2004) also considered lifetime exposure to racism as well as pregnancy exposure in a case-control study of 104 African American women in Chicago who delivered very low birth weight preterm infants and 208 matched controls who delivered normal birth weight infants. Lifetime exposure to racial discrimination in three or more domains of life was associated with very low birth weight (OR = 3.2; OR = 2.6 adjusted for age, education, and cigarette smoking). The outcomes were not associated with perceived prenatal racial discrimination. The authors conducted post hoc tests, whose results suggested that the effects detected were not attributable to recall bias because of infant illness among the low birth weight infants. In addition, the strongest risk was for college-educated African American women. Collins and colleagues (2004) conclude that “lifelong accumulated experiences of racial discrimination by African American women constitute an independent risk factor for preterm delivery” (p. 2132). One apparent pathway whereby racism appears to influence health and possibly prenatal processes is by cardiovascular functioning (Krieger, 1990; Krieger and Sidney, 1996). (For a complete review of the literature on racial and ethnic disparities in pregnancy outcomes, definitions and measures of racism, the conceptualization of racism as stress, and findings, see the work of Giscombe and Lobel ).
The following are key questions to be resolved in future research: Is racism a risk factor for preterm birth or fetal growth restriction or both, and, if so, by what pathways? Does racism act in association with other factors, such as social class, age, medical risk factors, or other stress or emotional factors to pose a risk? If racism is a potent risk factor, are there effective, practical, and cost-effective ways to mitigate its effects on maternal and infant outcomes?
In general, the emerging literature on racism and preterm delivery suggests that racism may be a potent stressor throughout the lifetimes of African American women that contributes to an explanation of the racial and ethnic disparities in the rates of both preterm birth and low birth weight. However, further study is needed to replicate and extend the existing studies. One challenge researchers face is the difficulty of assessing experiences of racism. Many factors contribute to underreporting of the experience. This challenge requires further precise work by investigators in future.