Antibiotic Regimens for Mothers with Chorioamnionitis
The first-line antibiotic regimen for mothers with chorioamnionitis is intravenous ampicillin (2g every 6 hours) plus gentamicin (1.5mg/kg every 8 hours or 5mg/kg ideal body weight daily), with clindamycin (900mg every 8 hours) added at cord clamping for cesarean deliveries. 1
First-Line Treatment Options
- Ampicillin (2g IV every 6 hours) plus gentamicin is the recommended first-line antimicrobial regimen for treatment of chorioamnionitis 1, 2
- Daily dosing of gentamicin using ideal body weight (5mg/kg) has been shown to be associated with a lower risk of postpartum endometritis compared to traditional 8-hour dosing 3
- For cesarean deliveries, clindamycin (900mg IV) should be administered at the time of umbilical cord clamping to provide additional anaerobic coverage 4, 1
Alternative Regimens for Penicillin-Allergic Patients
- For penicillin-allergic patients without history of severe reactions (anaphylaxis, angioedema, respiratory distress, or urticaria), cefazolin is the preferred agent 5
- For penicillin-allergic patients with history of severe allergic reactions, alternative regimens such as clindamycin or vancomycin should be considered 5
- Broader spectrum agents might be necessary for treatment of chorioamnionitis in certain clinical scenarios 5
Duration of Antibiotic Therapy
- For vaginal deliveries, evidence supports that one additional dose of antibiotics postpartum is sufficient therapy for immune-competent women with chorioamnionitis 4, 6
- For cesarean deliveries, continuing antibiotics until the patient is afebrile and asymptomatic for 24 hours has traditionally been recommended, though some evidence suggests a limited course may be sufficient for many patients 4, 6
- In a study of 292 women with chorioamnionitis, treatment failure rates did not differ between those who received one additional dose postpartum versus those who continued antibiotics until afebrile for 24 hours (4.6% vs 3.5%) 4
Emerging Treatment Options
- Some research suggests a regimen including ceftriaxone, clarithromycin, and metronidazole may provide better coverage against commonly identified microorganisms in chorioamnionitis 1
- Piperacillin-tazobactam is a broad-spectrum antibiotic that crosses the placenta in humans and may be considered in certain clinical scenarios, though there are insufficient data in pregnant women to fully establish safety profile 7
Important Considerations
- Chorioamnionitis cannot be cured by antibiotic therapy alone without delivery, so prompt delivery should be considered once diagnosis is established 2
- Antibiotic preferences may vary based on local policy, clinician experience, bacterial causes, antimicrobial resistance patterns, maternal allergies, and drug availability 2
- Neonates born to mothers with chorioamnionitis should undergo a limited evaluation (blood culture and CBC with differential and platelet count) and receive antibiotic therapy pending culture results 8, 9
Pitfalls and Caveats
- Treatment failure is more common after cesarean delivery (15%) compared to vaginal delivery (1%), suggesting that some patients who deliver by cesarean may benefit from a more extended course of antibiotic therapy 6
- Obesity, prolonged labor, or prolonged rupture of membranes may increase risk of treatment failure and serious complications such as wound infection or septic thrombophlebitis 6
- Consultation with obstetric providers is important to determine the level of clinical suspicion for chorioamnionitis, as some signs are nonspecific 5