In contrast, in the setting of PPROM, the chorion layer is thinner at all sites, or throughout the fetal membrane, indicating a more global, not localized, process is occurring. Surprisingly, this finding persists even in the absence of histopathologically confirmed infection. The chorion appears to be preferentially reduced in PPROM subjects throughout the membranes as compared to their preterm and term cohorts, implying that the chorion layer is primarily undergoing change.