What is the recommended treatment for bacterial infections during pregnancy?

Bactrim (Trimethoprim-Sulfamethoxazole) Use in Pregnancy

Trimethoprim-sulfamethoxazole (TMP-SMX/Bactrim) should be avoided during pregnancy, particularly near delivery, and used only when no safer alternatives exist for serious bacterial infections. 1

Safety Profile and Timing Considerations

First Trimester

• TMP-SMX is classified as a second-line agent during pregnancy and should be avoided when possible 2
• Trimethoprim interferes with folic acid metabolism, raising theoretical concerns about neural tube defects 2
• Use only if penicillins, cephalosporins, and other first-line agents have failed or are contraindicated 2

Near Delivery (Third Trimester)

• Sulfonamides carry a theoretical increased risk for neonatal hyperbilirubinemia and kernicterus when used near delivery 1
• Neonatal care providers must be informed if maternal sulfa therapy is used near delivery to monitor for these complications 1
• This risk is particularly concerning in the peripartum period 1

Preferred Alternatives During Pregnancy

First-Line Antibiotics

• Beta-lactam antibiotics (penicillins and cephalosporins) are the preferred first-line agents throughout pregnancy 1, 2, 3
• Penicillins have an established safety profile and should be used preferentially 4, 2
• First-generation cephalosporins (e.g., cefazolin) are appropriate alternatives for non-anaphylactic penicillin allergy 4, 5
• Third-generation cephalosporins (ceftriaxone) provide broader coverage when needed 1, 6

Second-Line Options

• Azithromycin is safe and effective for many infections during pregnancy 1, 5
• Clindamycin can be used if bacterial isolates are susceptible, though it should be used cautiously during the first trimester 7, 3
• Metronidazole is permitted during pregnancy when indications are strictly verified 2, 3

When TMP-SMX May Be Considered

Acceptable Scenarios

• Serious bacterial enteric infections in HIV-infected pregnant women when organism susceptibility testing supports its use 1
• Life-threatening infections where no safer alternative exists and susceptibility testing confirms efficacy 2
• Treatment should be guided by drug susceptibility testing of cultured isolates 1

Clinical Monitoring

• If TMP-SMX must be used near delivery, coordinate closely with neonatal care providers 1
• Monitor newborns for signs of hyperbilirubinemia and kernicterus 1

Common Pitfalls to Avoid

• Do not use TMP-SMX as empiric first-line therapy during pregnancy 2, 3
• Avoid prescribing in the weeks immediately preceding delivery unless absolutely necessary 1
• Do not assume all antibiotics are equally safe—pregnancy requires specific antibiotic selection based on trimester and fetal risk 2, 8
• Remember that approximately 10% of patients report penicillin allergy, but over 90% are not truly allergic—verify allergy history before avoiding beta-lactams 5, 3

Antibiotics to Strictly Avoid in Pregnancy

• Tetracyclines are contraindicated after the fifth week of pregnancy due to fetal tooth staining and bone accumulation 1, 2, 3
• Fluoroquinolones should be strictly avoided despite limited human data showing no clear teratogenicity, as they remain contraindicated as a precautionary measure 2, 3
• Aminoglycosides should be reserved only for life-threatening maternal infections due to nephrotoxicity and ototoxicity risks 2, 3