What is the definition of chorioamnionitis (inflammation of the chorion and amnion) in the mother?

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From the Guidelines

Chorioamnionitis is defined as an intraamniotic infection, which is typically documented by a physician and prompts treatment with antibiotics, and is characterized by symptoms such as fever, uterine tenderness, fetal tachycardia, and foul-smelling amniotic fluid. According to the most recent study 1, maternal morbidity, which includes chorioamnionitis, is a common outcome after expectant management of preterm prelabor rupture of membranes (PPROM) at less than 24 weeks of gestation. The study found that 60% of women with PPROM at less than 24 weeks of gestation developed maternal morbidity, which includes chorioamnionitis.

Key Characteristics of Chorioamnionitis

  • Intraamniotic infection
  • Documented by a physician
  • Prompts treatment with antibiotics
  • Symptoms include:
    • Fever
    • Uterine tenderness
    • Fetal tachycardia
    • Foul-smelling amniotic fluid

Risk Factors for Chorioamnionitis

  • Prolonged labor
  • Multiple vaginal exams during labor
  • Premature rupture of membranes
  • Certain sexually transmitted infections

Treatment of Chorioamnionitis

  • Broad-spectrum antibiotics such as ampicillin (2g IV every 6 hours) plus gentamicin (1.5mg/kg IV every 8 hours)
  • Treatment should continue until at least 24-48 hours after delivery

The diagnosis of chorioamnionitis is typically made clinically, based on signs and symptoms such as fever, uterine tenderness, fetal tachycardia, and foul-smelling amniotic fluid 1. It is essential to note that chorioamnionitis can lead to serious complications for both mother and baby if left untreated, making early diagnosis and treatment crucial for preventing these adverse outcomes.

From the Research

Definition of Chorioamnionitis

  • Chorioamnionitis is defined as the inflammatory response to an acute inflammation of the membranes and chorion of the placenta 2.
  • It is also described as an acute inflammation of the chorion, with or without involvement of the amnion, and is evidence of a maternal immunological response to infection 3.
  • Chorioamnionitis can exist in histologic, clinical, and subclinical forms 4.

Diagnosis of Chorioamnionitis

  • The clinical criteria for chorioamnionitis include maternal fever combined with 2 or more findings of maternal tachycardia, fetal tachycardia, leukocytosis, uterine tenderness, and/or malodorous amniotic fluid 5.
  • Chorioamnionitis can be diagnosed clinically, microbiologically, or by histopathologic examination of the placenta and umbilical cord 5.
  • Antenatal diagnosis of chorioamnionitis is limited, but fetal and placental imaging, such as ultrasound and MRI, may provide valuable information regarding the diagnosis of fetal inflammatory response 3.

Implications of Chorioamnionitis

  • Chorioamnionitis is associated with adverse maternal, perinatal, and long-term outcomes, including preterm birth, neonatal sepsis, pneumonia, bronchopulmonary dysplasia, perinatal death, cerebral palsy, and intraventricular hemorrhage 2.
  • Maternal complications include abnormal progression of labour, caesarean section, postpartum hemorrhage, abnormal response after use of oxytocin, and placenta abruption 2.
  • Prompt administration of antibiotics and steroids may improve neonatal outcomes 2.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Chorioamnionitis and prematurity: a critical review.

The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians, 2012

Research

Chorioamnionitis and labor.

Obstetrics and gynecology clinics of North America, 2005

Research

Chorioamnionitis at Term: Definition, Diagnosis, and Implications for Practice.

The Journal of perinatal & neonatal nursing, 2016

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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