Thus, we performed this study to (1) compare the levels of HMGB1 in amniotic fluid of patients with intra-amniotic inflammation to those in healthy controls, (2) compare HMGB1 expression in amnion membrane of patients with preterm birth and chorioamnionitis to normal term controls, and (3) investigate the expression of the miR-548 cluster in amnion membrane and explore the regulation of HMGB1 expression by the miR-548 cluster. Here, HMGB1 is linked to chorioamnionitis.