Racial/ethnic disparities in preterm birth: clues from environmental exposures

Purpose of review Despite advances in medical care, preterm birth and its associated racial/ethnic disparities remain major public health issues. Environmental exposures may contribute to racial disparities in preterm birth. Recent findings Recent work in Iran demonstrated lead levels less than 10 mu g/dl to be associated with preterm birth and premature rupture of membranes. Data on air pollution are mixed. A study in California found exposure to nitric oxide species to be associated with preterm birth. However, results from large birth cohorts in the Netherlands found no association. Interestingly, a study in South Korea recently demonstrated that socioeconomic status modifies the association between air pollution and preterm birth. A recent promising study randomized minority pregnant women in Washington, District of Columbia, to cognitive behavioral therapy vs. usual care to decrease exposure to environmental tobacco smoke (ETS). The investigators reported reductions in ETS exposure and the risk of very preterm birth. Summary Clues about potential mechanisms underlying disparities in preterm birth can be gained from exploring differences in environmental exposures. Investigators should include environmental variables when studying birth outcomes. Such efforts should result in targeted interventions to decrease the incidence of preterm birth and its disparities.