BPI and infection: Considering the overexpression of a broad spectrum of neutrophil granule-related genes (ELANE, BPI, MMP8, CRISP3, and CEACAM8) as well as DEFA3 in the CI group, following disruption of the cervical barrier, ascending vaginal microorganism infection may occur, causing intra-uterine inflammation/infection, maternal systemic inflammatory response, and neutrophil activation.