Chorioamnionitis is a general term that refers to inflammation of the chorion (the outer membrane of the fetal membranes) and amnion (innermost membrane of the fetal membranes). It is commonly caused by an ascending vaginal or cervical bacteria infecting fetal membranes or amniotic fluids. Common culprit bacteria include Ureaplasma urealyticum, Mycoplasma hominis, Gardnerella vaginalis, bacteroides, and group B Streptococcus. The most common symptoms are fever and uterine tenderness. It can cause significant problems for both the mother and baby, including preterm labor, premature birth, infection of the baby after birth, and even death.