The role of socioeconomic factors in Black-White disparities in preterm birth.

Objectives: We investigated the role of socioeconomic factors in Black-White disparities in preterm birth (PTB).
Methods: We used the population-based California Maternal and Infant Health Assessment survey and birth certificate data on 10 400 US-born Black and White California residents who gave birth during 2003 to 2010 to examine rates and relative likelihoods of PTB among Black versus White women, with adjustment for multiple socioeconomic factors and covariables.
Results: Greater socioeconomic advantage was generally associated with lower PTB rates among White but not Black women. There were no significant Black-White disparities within the most socioeconomically disadvantaged subgroups; Black-White disparities were seen only within more advantaged subgroups.
Conclusions: Socioeconomic factors play an important but complex role in PTB disparities. The absence of Black-White disparities in PTB within certain socioeconomic subgroups, alongside substantial disparities within others, suggests that social factors moderate the disparity. Further research should explore social factors suggested by the literature-including life course socioeconomic experiences and racism-related stress, and the biological pathways through which they operate-as potential contributors to PTB among Black and White women with different levels of social advantage.