How should I evaluate and initially treat a reproductive‑aged woman with fever, uterine tenderness, foul lochia or vaginal discharge, and leukocytosis suggestive of endometritis?

Evaluation and Initial Treatment of Postpartum Endometritis

Begin immediate empiric broad-spectrum antibiotics with intravenous clindamycin plus gentamicin after obtaining blood cultures in any reproductive-aged woman presenting with fever ≥38.3°C (≥101°F) or >38.0°C on more than two occasions >6 hours apart after the first 24 hours postpartum, combined with uterine tenderness and foul-smelling lochia. 1, 2, 3

Clinical Diagnosis

The diagnosis of postpartum endometritis is primarily clinical and does not require imaging or invasive testing in straightforward presentations. 1

Diagnostic criteria include:

• Fever ≥38.3°C (≥101°F) OR >38.0°C on more than two occasions >6 hours apart, occurring after the first 24 hours post-delivery and up to 10 days postpartum 4, 1
• Uterine tenderness on examination 1
• Foul-smelling lochia 4, 1
• Abdominal pain 4

Key risk stratification:

• Cesarean section (especially unplanned/emergent) carries 5-7 times higher risk than vaginal delivery 5, 6
• Risk is highest when cesarean performed after labor onset or membrane rupture 5, 6

Initial Evaluation

Obtain the following before antibiotics (if hemodynamically stable):

• Blood cultures (two separate venipuncture collections) 1, 6
• Complete blood count with differential 6
• Metabolic panel and lactate level 6

Critical caveat: Endocervical or D&C cultures have limited utility and should NOT be routinely obtained, as they do not reliably reflect upper genital tract pathogens. 4, 1 This is a polymicrobial infection involving mixed anaerobic organisms, vaginal flora, Enterobacteriaceae, enterococci, and group A/B streptococci. 4, 1, 7

Immediate Antibiotic Treatment

First-line regimen (gold standard):

• Intravenous clindamycin (900 mg every 8 hours) PLUS gentamicin (once-daily dosing preferred over thrice-daily) 8, 2, 3

This combination provides superior outcomes compared to other regimens, with treatment failure rates of only 6-7% versus 10-15% with alternative antibiotics. 2, 3 The regimen has excellent activity against penicillin-resistant anaerobic bacteria (particularly Bacteroides fragilis), which is critical for treatment success. 8, 2, 3

Why this regimen is superior:

• Regimens with poor activity against penicillin-resistant anaerobes have nearly twice the treatment failure rate (RR 1.94) 2, 3
• Once-daily gentamicin dosing shows fewer treatment failures than thrice-daily dosing 4, 2, 3
• Over 60% of cases involve Gardnerella vaginalis and/or anaerobes associated with bacterial vaginosis, which require robust anaerobic coverage 7

Duration and Monitoring

Discontinue IV antibiotics once:

• Patient has been afebrile for 24 hours with clinical improvement 1, 8, 2
• NO oral antibiotic continuation is needed after IV therapy 1, 2, 3

Expected response:

• Substantial improvement should occur within 72 hours of initiating therapy 1
• 93.7% of cases respond to initial antibiotics 6

Treatment Failure Management

If no improvement by 72 hours, immediately:

• Obtain imaging (CT or MRI pelvis preferred over ultrasound) to evaluate for complications 4, 1
• Perform blood cultures to assess for unusual pathogens or bacteremia 1
• Consider alternative diagnoses 1

Complications to evaluate for:

• Parametrial or pelvic abscess 4, 1
• Infected hematoma 4, 1
• Septic pelvic/ovarian vein thrombosis (can cause pulmonary embolism) 4, 5
• Retained products of conception (though difficult to differentiate from blood products on imaging) 4, 5
• Wound infection (especially after cesarean) 3

Common Pitfalls to Avoid

• Do not delay antibiotics for culture results - this is a clinical diagnosis requiring immediate treatment 1, 6
• Do not use regimens with poor anaerobic coverage (e.g., second/third generation cephalosporins excluding cephamycins have 66% higher failure rates) 3
• Do not prescribe oral antibiotics after IV therapy completion - this provides no additional benefit 1, 2, 3
• Do not obtain endocervical cultures - they have limited diagnostic utility 4, 1
• Do not dismiss persistent fever beyond 72 hours - this mandates imaging and reassessment 1