- Chorioamnionitis, defined as either 1) clinical diagnosis of choriomanionitis 2) maternal fever greater than or equal to 100 degrees F in the presence of rupture of membranes or 2 of the following: uterine tenderness, maternal WBC > 15,000 cells/mm, fetal tachycardia > 160 bpm, malodorous amniotic fluid, or in preterm group only, rupture of membranes and active preterm labor.