Although less than 1% of all singleton infants born in 1980 in the United States were very low birthweight (<1500g), they accounted for 40% of all infant deaths. Black infants constitute a disproportionate percentage of very low birthweight and preterm infants. While preterm delivery among white women has remained stable, preterm delivery has been on the rise among black women. Thus, black-white gap infant mortality could be substantially reduced if deaths among very low birth weight infants could be prevented. However, the gap will not be diminished until the rate of premature delivery among black women decreases.

A poverty-driven paradigm has defined our public health approach to dealing with maternal and child health in the United States for the last hundred years. The disadvantaged and poor segments of our population have higher rates of mortality and low birthweight. The authors explore whether the poverty- driven paradigm is a valid and efficient approach to handle poor birth outcomes. First, in order for the paradigm to be valid, statistical findings must confirm the existence of social class differential in risk factors for infant mortality. Then poverty-driven improvement programs must be shown to be effective. Finally, unequal access to these amelioration programs or interventions must be shown to exist.

The paradigm breaks down when it is applied to pregnancy outcomes among the black population. Public health experts have often equated being black in the U.S. with being poor and have thus attributed the excess infant mortality among blacks to poverty. To control for the effects of poverty, Schoendorf et al. examined the mortality rates of singleton infants of college-educated black and white parents. While the infant mortality rates were similar for many causes that were unrelated to low birthweight, overall an excess infant mortality rate still persisted. The excess was attributed to the higher rate of low birthweight, in particular very low birthweight among college-educated black parents. Hence, the poverty paradigm does not appear to endure for infant mortality due to preterm delivery.

Therefore, the authors examined other possible explanations for the higher rate of preterm delivery among black women, regardless of their financial status. They felt that a more accurate view is that the high rate of preterm delivery and its related contribution to infant mortality among blacks is a socio-biological phenomenon. Researchers have observed a complex relationship between maternal psychosocial stress and pregnancy outcome. Stress may alter physiologic processes and also lead to high-risk behaviors. And “psychosocial stress may result from negative social interactions, such as racism.” Furthermore, the work of Polednak sustains the argument that political structure and economic forces affect biological processes. A narrower racial gap in infant mortality was observed between blacks and whites that lived in residentially integrated, metropolitan areas, independent of the economic status of the area. Physical stressors such as poor nutrition, exposure to environmental toxins, poor housing, and adverse occupational conditions may themselves increase the risk of preterm delivery. They may also interact with psychological stress to exacerbate the risk. Very low birthweight has been often used as a proxy for preterm delivery, but very low birthweight does not address all birth outcomes associated with preterm delivery. While preterm delivery may result from idiopathic preterm labor, premature rupture of the membranes or other medical conditions, the causal mechanisms of preterm delivery are largely unknown. Knowledge of its etiology is particularly important with respect to black women since they sustain most of the burden of preterm delivery.

Since the 1970s, advances in medical technology have improved infant survival, especially among those of low birthweight. However, interventions or strategies to reduce the incidence of preterm delivery, for which the risk is twice as high among black than white women, have not succeeded. Also, poverty alone has not been a significant cause of differential birth outcomes among black and white women. Thus, future research must emphasize the biologic and social factors that are environmental exposures and the social context that lead to a higher risk of premature delivery for black women than white women. “We need a clearer picture of the effects of chronic stress, acute stress, and chronic strain. Major sources of stress among African-American women (racial and sexual discrimination) and protective responses may not be captured by previously used scales.” Social and environmental stressors are not disease-specific. Thus, an understanding of the ways in which these stressors affect physiological processes of black women in particular may help to alleviate adverse pregnancy outcomes as well as other adverse health conditions among blacks in the United States.