In both rural and urban areas, and for both all infants as well as just African American infants, those born to users of primary care health centers are less likely to be of low birthweight than infants of mothers who are not users of those centers.

Source: Politzer RM, Yoon J, Shi L, Hughes RG, Regan J, Gaston MH. Inequality in America: the contribution of health centers in reducing and eliminating disparities in access to care. Med Care Res Rev 2001; 58(2):234-248.