Effects of social and psychosocial factors on risk of preterm birth in black women.

Our objective was to examine how social and psychosocial factors may influence the risk of preterm birth. The design of the study was a hybrid retrospective and prospective cohort. African-American women residing in Baltimore, Maryland, were enrolled prenatally if they received care at one of three Johns Hopkins Medical Institution prenatal clinics (n=384) or enrolled post-partum if they delivered at Johns Hopkins Medical Institution with late, none or intermittent prenatal care (N=459). Preterm birth was defined as less than 37 weeks completed gestation. Interview data were collected on 832 enrolled women delivering singletons between March 2001 and July 2004. The preterm birth rate was 16.4%. In both unadjusted and adjusted models, exposure to racism over a woman's lifetime had no effect on risk of preterm birth in our sample. However, we found evidence of a three-way interaction between reported lifetime experiences of racism, depressive symptoms during pregnancy and stress during pregnancy on preterm birth risk. Racism scores above the median (more racism) were associated with an increased risk of preterm birth in three subgroups with the effect moderated by depressive symptoms and stress. Social and psychosocial factors may operate in a complex manner related to risk of preterm birth.