IL1B and chorioamnionitis: It is well-documented that chorioamnionitis, possibly due to the infiltration of leukocytes into the chorion and amnion (1, 64), is associated with an increased abundance of IL-1 in amniotic fluid (5, 46, 64–70), in addition to preterm labor (46, 70) and preterm pre-labor rupture of membranes (PPROM) (5).