Chorioamnionitis

Background

• Also known as intra-amniotic infection
• Bacterial infection of fetal amnion and chorion membranes
• Most commonly an ascending infection from normal vaginal flora

Risk Factors

• Young age
• Low socioeconomic status
• Multiple vaginal examinations
• Nulliparity
• Extended duration of labor and ruptured membranes
• Pre-existing genital tract infections

Microbiology

• Polymicrobial
• Genital mycoplasmas, anaerobes, enteric gram-negative bacilli and group B strep

Clinical Features

Signs and Symptoms

• Maternal fever (intra-partum temperature >100.4 °F or >37.8 °C)
• Significant maternal tachycardia (>120 beats/min)
• Fetal tachycardia (>160-180 beats/min)
• Purulent or foul-smelling amniotic fluid or vaginal discharge
• Uterine tenderness
• Maternal leukocytosis (total blood leukocyte count >15,000-18,000 cell/µL)

Presentation

• Severity of presentation is broad. Patient may appear toxic or may have silent chorioamnionitis, which still puts fetus at risk for neonatal sepsis.

Differential Diagnosis

Abdominal Pain in Pregnancy

The same abdominal pain differential as non-pregnant patients, plus:

<20 Weeks

• Ectopic pregnancy
• First trimester abortion
  • Complete abortion
  • Threatened abortion
  • Inevitable abortion
  • Incomplete abortion
  • Missed abortion
  • Septic abortion
• Round ligament stretching
• Incarcerated uterus
• Malposition of the uterus

>20 Weeks

• Labor/Preterm labor
• Placental abruption
• Placenta previa
• Vasa previa
• Uterine rupture
• Vaginal trauma
• HELLP syndrome
• Cholestasis of pregnancy
• Chorioamnionitis
• Incarcerated uterus
• Acute fatty liver of pregnancy
• Malposition of the uterus
• Placenta accreta
• Placenta increta
• Placenta percreta

Any time

• Hemorrhagic ovarian cyst
• Fibroid degeneration or torsion
• Ovarian torsion
• Constipation
• Extra-amniotic infections such as pyelonephritis, appendicitis, pneumonia

Workup

• CBC
• Blood cultures
• Vaginal fluid for phosphatidylglycerol
  • Tests for fetal lung maturity
• Cervical cultures
  • E. coli
  • Gonorrhea
• Vaginal cultures
  • Chlamydia
  • Mycoplasma
  • Group B streptococci
• Ultrasonography for fetal well-being

Exam

• Avoid digital cervical exam
• Speculum exam should be done with sterile speculum

Management

• Ampicillin IV 2g Q6H AND Gentamicin IV 1.5 mg/kg Q8H
• Alternative antibiotic regimens:
  • Ampicillin-sulbactam IV 2g Q6H
  • Ticarcillin-clavulanate IV 3.1g Q4H
  • Cefoxitin IV 2g Q4H
• Can only be considered cured with delivery of infected products of conception

Disposition

Given concern for neonatal sepsis, patients should be admitted for IV antibiotics, supportive care, and possible early delivery

Complications

• Placental abruption
• Premature birth
• Neonatal sepsis
• Neonatal death
• Cerebral palsy
• Maternal sepsis
• Need for cesarean delivery
• Postpartum hemorrhage

See Also

• Abdominal pain in pregnancy

Sources

• Rosen’s
• Tintinalli’s
• UpToDate
• Abbrescia K, Sheridan B. Complications of second and third trimester pregnancies. Emerg Med Clin N Am 21 (2003): 695-710.
• Apantaku O, Mulik V. Maternal intra-partum fever. J Obstet Gynaecol. 2007 Jan; 27(1):12-5.