Limited course of antibiotic treatment for chorioamnionitis

We sought to estimate the effectiveness of a limited course of antibiotics in treating patients with chorioamnionitis.

We conducted a retrospective review of patients treated for chorioamnionitis at our medical center from 2005 to 2009. Patients received ampicillin plus gentamicin as soon as the diagnosis was made. Postpartum they received only the next scheduled dose of each antibiotic. Patients who underwent a cesarean delivery received either metronidazole or clindamycin immediately after cord clamping. The primary outcome was treatment failure, defined as persistent fever requiring continuation of antibiotics, surgical intervention, or administration of heparin.

Of the 423 patients, 282 delivered vaginally, and 141 delivered by cesarean. Overall, 399 (94%; 95% confidence interval [CI], 92-96%) were treated successfully and 24 (6%; 95% CI 3.7-8.3%) failed short-course treatment. Of the 282 patients who delivered vaginally, 279 (99%; 95% CI 98-100%) were cured with short-term therapy. Of the 141 who delivered by cesarean, 120 (85%; 95% CI 79-91%) were cured (P<.001). Seventeen of the patients with total treatment failure had endometritis and responded to continuation of antibiotics. Seven patients had more serious complications: wound infection (n=4) and septic thrombophlebitis (n=3). All of the serious complications occurred after cesarean delivery, and all of the affected patients either were obese or had prolonged labor or prolonged rupture of membranes.

A limited course of antibiotics was sufficient for virtually all patients (99%) with chorioamnionitis who had a vaginal delivery. However, a subset of patients who delivered by cesarean may have benefited from a more extended course of antibiotic therapy.

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