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For further information, see CMDT Part 19-16: Chorioamnionitis & Metritis

Key Features

  • Chorioamnionitis is an infection of the amnion and chorion (fetal parts), usually occurring during labor

  • Uterine infection after delivery is often called endometritis or endomyometritis, but the term "metritis" is probably most accurate to emphasize that the infection extends throughout the uterine tissue

  • These infections are polymicrobial and are most commonly attributed to urogenital pathogens

  • Risk factors for puerperal infection

    • Cesarean delivery (most important risk factor; risk increased 5- to 2-fold)

    • Prolonged labor

    • Use of internal monitors

    • Nulliparity

    • Multiple pelvic examinations

    • Prolonged rupture of membranes

    • Lower genital tract infections

  • Neonatal complications are increased in the setting of chorioamnionitis and include

    • Sepsis

    • Pneumonia

    • Intraventricular hemorrhage

    • Cerebral palsy

Clinical Findings

  • Fever not attributable to another source

  • Uterine tenderness

  • Tachycardia in the mother, fetus, or both


  • Presence of fever (≥ 38°C) in the absence of any other source and one or more of the following signs:

    • Maternal or fetal tachycardia (or both)

    • Uterine tenderness

  • Foul-smelling lochia may be present, but is an insensitive marker of infection

  • Cultures are typically not done because of the polymicrobial nature of the infection


  • Empiric; broad-spectrum antibiotics that will cover

    • Gram-positive and gram-negative organisms if patient is still pregnant

    • Gram-negative organisms and anaerobes if patient is postpartum

  • For chorioamnionitis: ampicillin, 2 g intravenously every 6 hours, and gentamicin, 2 mg/kg intravenous load then 1.5 mg/kg intravenously every 8 hours

  • For metritis: gentamicin, 2 mg/kg intravenous load then 1.5 mg/kg intravenously every 8 hours, and clindamycin, 900 mg intravenously every 8 hours

  • Antibiotics are stopped in the mother when she has been afebrile (and asymptomatic) for 24 hours; no oral antibiotics are subsequently needed

  • Patients with metritis who do not respond in the first 24–48 hours may have an enterococcal component of metritis and require additional gram-positive coverage (such as ampicillin) to the regimen

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