chorioamnionitis

Chorioamnionitis, also known as amnionitis and intra-amniotic infection (IAI), is inflammation of the fetal membranes (amnion and chorion), usually due to bacterial infection. In 2015, a National Institute of Child Health and Human Development Workshop expert panel recommended use of the term "triple I" to address the heterogeneity of this disorder. The term triple I refers to intrauterine infection or inflammation or both and is defined by strict diagnostic criteria, but this terminology has not been commonly adopted although the criteria are used.

Chorioamnionitis results from an infection caused by bacteria ascending from the vagina into the uterus and is associated with premature or prolonged labor. It triggers an inflammatory response to release various inflammatory signaling molecules, leading to increased prostaglandin and metalloproteinase release. These substances promote uterine contractions and cervical ripening, causations of premature birth. The risk of developing chorioamnionitis increases with number of vaginal examinations performed in the final month of pregnancy, including labor. Tobacco and alcohol use also puts mothers at risk for chorioamnionitis development.