When comparing preterm labor with sterile intra-amniotic inflammation to preterm labor without either intra-amniotic inflammation or proven intra-amniotic infection, median concentrations of 5 cytokines [e.g. MIP-3α (log2 FC = 3.6), Calgranulin C (log2 FC = 2.6), and IL-1β (log2 FC = 0.9)] were significantly increased. Here, IL1B is linked to inflammation.