Chapter 204 Chorioamnionitis
INTRODUCTION
Description: Chorioamnionitis is inflammation of the fetal membranes. This may be associated with prolonged or premature rupture of the membranes or a primary cause of premature labor.
ETIOLOGY AND PATHOGENESIS
Causes: Infection by organisms ascending from the vaginal canal, most often when the membranes have been ruptured. Studies indicate that bacteria (specifically Escherichia coli) can permeate intact chorioamnionic membranes. Infection may also occur by hematogenous, transabdominal, or transfallopian routes.
DIAGNOSTIC APPROACH
Workup and Evaluation
Laboratory: White blood count and red cell sedimentation rate. Gram stain of amniotic fluid (a negative test carries a 99% specificity). Cultures may be obtained and may be of assistance in management, but the diagnosis is often made on clinical grounds. (Amniocentesis for culture has not been shown to improve pregnancy outcome. There is no clear evidence to support the use of C-reactive protein for the early diagnosis of chorioamnionitis.)
Special Tests: A biophysical profile of the fetus may be of assistance in planning management (if time and maternal condition permit).
