In this study, by examining precise sites within the same human fetal membrane, we found the fetal chorion layer to be differentially thinned at membrane rupture site as compared to more distant sites among all subjects suggesting that the chorion around the rupture site undergoes significant remodeling throughout gestation. 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