Micrograph showing acute chorioamnionitis, with neutrophils in the chorion. Also seen are fibrin thrombi, which indicate a severe fetal inflammatory response.[1]H&E stain.
Chorioamnionitis, also known as amnionitis and intra-amniotic infection (IAI), is inflammation of the fetal membranes (amnion and chorion), usually due to bacterialinfection.[1] 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.[2]
Chorioamnionitis results from an infection caused by bacteria ascending from the vagina into the uterus and is associated with premature or prolonged labor.[3] 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.[4] The risk of developing chorioamnionitis increases with number of vaginal examinations performed in the final month of pregnancy, including labor.[5][6] Tobacco and alcohol use also puts mothers at risk for chorioamnionitis development.[7]
Chorioamnionitis is caught early by looking at signs and symptoms such as fever, abdominal pain, or abnormal vaginal excretion.[8] Administration of antibiotics if the amniotic sac bursts prematurely can prevent chorioamnionitis occurrence.[9]
^Cheng YW, Delaney SS, Hopkins LM, Caughey AB (November 2009). "The association between the length of first stage of labor, mode of delivery, and perinatal outcomes in women undergoing induction of labor". American Journal of Obstetrics and Gynecology. 201 (5): 477.e1–477.e7. doi:10.1016/j.ajog.2009.05.024. PMID19608153.
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^Seaward PG, Hannah ME, Myhr TL, Farine D, Ohlsson A, Wang EE, et al. (November 1997). "International Multicentre Term Prelabor Rupture of Membranes Study: evaluation of predictors of clinical chorioamnionitis and postpartum fever in patients with prelabor rupture of membranes at term". American Journal of Obstetrics and Gynecology. 177 (5): 1024–1029. doi:10.1016/s0002-9378(97)70007-3. PMID9396886.