Treatment of GBS UTI at 25 Weeks Gestation
This patient requires immediate antibiotic treatment of the UTI now, followed by mandatory intrapartum IV antibiotic prophylaxis during labor, regardless of whether the UTI is treated today. 1, 2
Immediate Treatment of the Acute UTI
Treat the symptomatic or asymptomatic GBS UTI now according to standard pregnancy UTI protocols:
- Penicillin G is the preferred first-line agent due to its narrow spectrum and universal GBS susceptibility 2
- Ampicillin (oral formulation for outpatient UTI treatment) is an acceptable alternative 2
- Complete the full prescribed antibiotic course to ensure eradication and prevent recurrence 2
Critical understanding: GBS bacteriuria at any concentration during pregnancy is a marker for heavy genital tract colonization and significantly increases the risk of early-onset neonatal GBS disease 1, 2. However, treating this UTI now will NOT eliminate GBS colonization from the genitourinary tract—recolonization after oral antibiotics is typical 2.
Mandatory Intrapartum Prophylaxis (During Labor)
This patient must receive IV antibiotic prophylaxis during labor, even though you are treating the UTI today at 25 weeks:
First-Line Intrapartum Regimen (No Penicillin Allergy):
- Penicillin G 5 million units IV initially, then 2.5 million units IV every 4 hours until delivery 1, 2
- Alternative: Ampicillin 2 g IV initially, then 1 g IV every 4 hours until delivery 1, 2
- Penicillin G is preferred over ampicillin due to narrower spectrum and less likelihood of selecting antibiotic-resistant organisms 1
For Penicillin-Allergic Patients:
If NOT at high risk for anaphylaxis (no history of anaphylaxis, angioedema, respiratory distress, or urticaria to penicillin):
If at high risk for anaphylaxis (history of immediate hypersensitivity reactions):
- Clindamycin 900 mg IV every 8 hours (only if GBS isolate is susceptible to clindamycin and erythromycin) 2, 3
- Vancomycin 1 g IV every 12 hours (if susceptibility testing unavailable or isolate is resistant to clindamycin) 2, 3
- Susceptibility testing for clindamycin and erythromycin must be performed on the GBS isolate from penicillin-allergic women at high risk for anaphylaxis 2
Timing and Effectiveness
- Intrapartum prophylaxis must be administered ≥4 hours before delivery for maximum effectiveness 2
- When given ≥4 hours before delivery, prophylaxis is 78% effective in preventing early-onset neonatal GBS disease 2
- Although 4+ hours is optimal, even 2 hours of antibiotic exposure has been shown to reduce GBS vaginal colony counts and decrease clinical neonatal sepsis 4
- Do not delay necessary obstetric interventions solely to achieve 4 hours of antibiotic administration 4
No Need for Repeat Screening
- This patient does NOT need vaginal-rectal GBS screening at 36-37 weeks gestation 1, 2
- Women with GBS bacteriuria at any point during pregnancy are presumed to be heavily colonized and automatically qualify for intrapartum prophylaxis 1, 2
Critical Pitfalls to Avoid
- Do not assume that treating the UTI now eliminates the need for intrapartum prophylaxis—this is the most common and dangerous error 1, 2
- Do not use oral antibiotics before labor to attempt GBS eradication—this is ineffective and may promote antibiotic resistance 1, 2
- Do not underdose or prematurely discontinue therapy for the acute UTI, as this may lead to treatment failure 2
- Approximately 10% of penicillin-allergic patients also have immediate hypersensitivity to cephalosporins, making allergy risk stratification essential 3
- Many reported penicillin allergies are not true IgE-mediated reactions—consider verifying allergy history 3
Documentation Requirements
- Ensure the laboratory reports this GBS bacteriuria finding to both the anticipated site of delivery and the ordering provider 1
- Document clearly in the prenatal record that this patient requires intrapartum antibiotic prophylaxis during labor 2
- Communicate this requirement to the labor and delivery team well in advance 2