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Chorioamnionitis - high mag.jpg
Micrograph showing chorioamnionitis. The clusters of blue dots are inflammatory cells (neutrophils, eosinophils and lymphocytes). H&E stain.
Classification and external resources
ICD-10 O41.1, P02.7
ICD-9 658.4, 762.7
DiseasesDB 31882
eMedicine ped/89
MeSH D002821

Chorioamnionitis also known as intra-amniotic infection (IAI)[1] is an inflammation of the fetal membranes (amnion and chorion) due to a bacterial infection. It typically results from bacteria ascending into the uterus from the vagina and is most often associated with prolonged labor. The risk of developing chorioamnionitis increases with each vaginal examination that is performed in the final month of pregnancy, including during labor.[3]


The fetal membranes consist of two parts:

  • The outer membrane is the chorion. It is closest to the mother and physically supports the much thinner amnion.
  • The inner membrane is the amnion. It is in direct contact with the amniotic fluid, which surrounds the fetus.


Intermediate magnification micrograph of moderate chorioamnionitis. H&E stain.


Chorioamnionitis is diagnosed clinically in the setting of:[2]



Chorioamnionitis can be diagnosed from a histologic examination of the fetal membranes.

Infiltration of the chorionic plate by neutrophils is diagnostic of (mild) chorioamnionitis. More severe chorioamnionitis involves subamniotic tissue and may have fetal membrane necrosis and/or abscess formation.

Severe chorioamnionitis may be accompanied by vasculitis of the umbilical blood vessels (due to the fetus' inflammatory cells) and, if very severe, funisitis (inflammation of the umbilical cord's connective tissue).


Treatment consists of:

Evidence regarding which antibiotic is best or how long they are needed is not clear.[3]


Chorioamnionitis is a risk factor for periventricular leukomalacia and cerebral palsy.[4]

See also[edit]


  1. ^ "Intra–Amniotic Infection". Retrieved 20 December 2014. 
  2. ^ Elmar Peter Sakala, MD, MA, MPH, FACOG. Professor of GYNOB, Loma Linda University of medicine, California. Codirector of Student Clerkship. Dept of GYNOB
  3. ^ Chapman, E; Reveiz, L; Illanes, E; Bonfill Cosp, X (19 December 2014). "Antibiotic regimens for management of intra-amniotic infection.". The Cochrane database of systematic reviews 12: CD010976. PMID 25526426. 
  4. ^ Wu YW, Colford JM (2000). "Chorioamnionitis as a risk factor for cerebral palsy: A meta-analysis". JAMA 284 (11): 1417–24. doi:10.1001/jama.284.11.1417. PMID 10989405. 


  • Excess Digital Exams Raise Risk of Chorioamnionitis, Ob.Gyn. News, August 15, 1997
  • Centers for disease control and prevention (2002) Prevention of perinatal group B Streptococcal disease: revised guidelines from CDC. MMWR 51:RR-11:1–28

External links[edit]