IL1B and chorioamnionitis: Using a preclinical rat model of GBS-induced chorioamnionitis, we established that GBS inoculated intraperitoneally (i.p.)to the dam: (i) infects the placenta (24), (ii) rapidly induces the overexpression of IL-1β in the placentas (27) (iii) and leads to sexually dichotomous chorioamnionitis, with higher IL-1β release and PMN recruitment in male versus litter-matched female tissues (24, 27).