In the soluble fraction of amniotic fluid, median concentrations of 37 cytokines were significantly higher in preterm labor with intra-amniotic infection compared preterm labor without either intra-amniotic inflammation or proven intra-amniotic infection, with eotaxin-1, CXCL-6, and HMGB1 being the most increased (log2 FC >10 for all). This evidence concerns the gene HMGB1 and chorioamnionitis.