Chorioamnionitis also known as intra-amniotic infection (IAI) is an inflammation of the fetal membranes (amnion and chorion) due to a bacterial infection. It typically results from bacteria ascending from the vagina into the uterus 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.
|Micrograph showing chorioamnionitis. The clusters of blue dots are inflammatory cells (neutrophils, eosinophils and lymphocytes). H&E stain.|
|Specialty||Obstetrics and gynaecology |
The amniotic sac consists of two parts:
Signs and symptoms
- Maternal leukocytosis (>15,000 cells/mm³)
- Maternal tachycardia (>100 bpm)
- Fetal tachycardia (>160 bpm)
- Uterine tenderness
- Foul odor of amniotic fluid
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).
Antibiotic Treatment consists of:
- Standard: Ampicillin 2g IV every 6 hours + Gentamicin 1.5 mg/kg every 8 hours
- Alternative: Ampicillin-Sulbactam 3g IV every 5 hours, Ticarcillin-Clavulanate 3.1g IV every 4 hours, Cefoxitine 2g IV every 6 hours
- Cesarean Delivery: Ampicillin 2g IV every 6 hours + Gentamicin 1.5 mg/kg every 8 hours + Clindamycin 900 mg every 8 hours or Metronidazole 500 mg IV every 6 hours
- Penicillin-Allergy: Vancomycin 1g IV every 12 hours + Gentamicin 1.5 mg/kg every 8 hours
However, there is not enough evidence to support the most efficient antimicrobial regimen, starting the treatment during the intrapartum period is more effective than starting it postpartum; it shortens the hospital stay for the mother and the neonate. However, completion of treatment/cure is only considered after delivery.
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- Seaward, P. G., Hannah, M. E., Myhr, T. L., et al. (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. Am J Obstet Gynecol, 177(5), 1024-1029.
- Elmar Peter Sakala, MD, MA, MPH, FACOG. Professor of GYNOB, Loma Linda University of medicine, California. Codirector of Student Clerkship. Dept of GYNOB
- "UpToDate". Uptodate.com. Retrieved 2 July 2018.
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- 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