Over the past two decades in the United States there have been concerted efforts to reduce the number of preterm deliveries and low birth weight babies. Such births are the second leading cause of infant mortality across the population at large, and among African Americans the first cause. Furthermore, African American women are two to three times more likely than white women to deliver preterm. Although the overall number of preterm births has been reduced in the US the gap appears to have widened because preterm births have declined faster among white than African American women. A large number of epidemiological studies have attempted to account for this disparity in terms of maternal age, education, lifestyle, and or socio-economical position. However, the results make it clear that these variables account for only a small proportion of the difference. Moreover, college-educated black mothers are more likely to deliver very low birth weight infants than are college-educated white mothers. And, further, it has been shown that women recently immigrated to the US bear infants of higher birth weight than do women of the same race/ethnic category (as defined by the US census) born and raised in the United States, despite the frequency of lower socioeconomic status among the immigrants. Researchers involved with these studies argue that their findings "suggest that growing up as a woman of color in the US is somehow toxic to pregnancy, and imply a social etiology for racial/ethnic disparities in prematurity that is not solely explained by economics or education.
Regardless of their socioeconomic level, African Americans who reported the experience of racial discrimination in three or more situations proved to be at more than three times the risk for preterm delivery as compared to women who reported no experience of racism. Further, recent studies have supported this conceptual model. [Epidemiologist Nancy] Krieger's conclusion is that "biological expressions of race relations" appear to be at work in accounting for the findings about low birth weight and she goes on to caution that human biology should never be studied in the abstract. this example makes strikingly clear how individual women should not be held fully accountable for the outcomes of pregnancies. in the united states, and elsewhere too, no doubt, persistent experiences of racism in every day life continue to take their toll, despite dramatic political reforms throughout the latter part of the 20th century.
from Local Biologies and Human Differences By Margaret Lock, Nguyen Vinh-Kim