Williams Manual of Pregnancy Complications, 23 ed.

CHAPTER 15. Chorioamnionitis

Chorioamnionitis is inflammation of the fetal membranes, usually in association with prolonged membrane rupture and long labor. Occult (“silent”) chorioamnionitis, caused by a wide variety of microorganisms, has recently emerged as a possible explanation for many heretofore unexplained cases of ruptured membranes, preterm labor, or both. Chorioamnionitis increases fetal and neonatal morbidity substantially. Specifically, neonatal sepsis, respiratory distress, intraventricular hemorrhage, seizures, periventricular leukomalacia, and cerebral palsy are all more common in infants born to mothers with chorioamnionitis.

Clinical chorioamnionitis manifests as maternal fever with temperatures of 38°C (100.4°F) or higher, usually in the setting of ruptured membranes. Maternal fever during labor or following ruptured membranes is usually attributed to chorioamnionitis until proven otherwise. Fever is often associated with maternal and fetal tachycardia, foul-smelling lochia, and fundal tenderness. Maternal leukocytosis by itself has been found to be unreliable for diagnosis of chorioamnionitis.

The management of chorioamnionitis consists of antimicrobial therapy, antipyretics, and delivery of the fetus, preferably vaginally. Antibiotic therapy must provide coverage for the polymicrobial milieu found in the vagina and cervix. One such regimen includes ampicillin, 2-g intravenous every 6 hours, plus gentamicin 2-mg/kg loading dose and then 1.5-mg/kg intravenous every 8 hours. Clindamycin 900 mg every 8 hours is substituted in women allergic to penicillin. A variety of other broad-spectrum antimicrobial regimens can be used. Antibiotics are usually continued after delivery until the mother is afebrile.

For further reading in Williams Obstetrics, 23rd ed.,

see Chapter 27, “Abnormalities of the Placenta, Umbilical Cord and Membranes.”