What is the recommended treatment for a pregnant woman with a urinary tract infection (UTI)?

Treatment of Urinary Tract Infections in Pregnancy

For pregnant women with urinary tract infections, nitrofurantoin is the first-line treatment for asymptomatic bacteriuria and uncomplicated cystitis, while hospitalization with intravenous antibiotics (preferably cephalosporins) is required for pyelonephritis. 1, 2

Screening and Diagnosis

• All pregnant women should be screened for bacteriuria by urine culture at least once in early pregnancy (optimally around 16 weeks gestation) 3
• Proper specimen collection is essential:
  • Clean-catch midstream void with proper cleansing technique is preferred
  • Urine culture is the gold standard diagnostic test (not urinalysis alone) 1
  • Pyuria alone is insufficient for diagnosis (sensitivity only ~50%) 3

Treatment Algorithm for UTIs in Pregnancy

1. Asymptomatic Bacteriuria

• First-line: Nitrofurantoin 100mg BID for 5-7 days (avoid near term) 1, 4
• Alternatives:
  • Cephalexin or other first-generation cephalosporins 4
  • Amoxicillin (though 80% cure rate indicates higher resistance) 5
  • Avoid trimethoprim-sulfamethoxazole in first and third trimesters 1, 5

2. Uncomplicated Cystitis (Lower UTI)

• First-line: Nitrofurantoin 100mg BID for 5-7 days 1, 2
• Alternatives:
  • Beta-lactams (amoxicillin 500mg TID for 3-7 days) 5
  • Cephalosporins (cephalexin, cefuroxime) 1, 4
• Follow-up: Repeat urine culture 7 days after treatment to confirm cure 5

3. Pyelonephritis (Upper UTI)

• Requires hospitalization and IV antibiotics 2, 4
• First-line: Second or third-generation cephalosporins IV 4
• Alternatives: Based on culture and sensitivity results
• Duration: IV antibiotics until afebrile for 24-48 hours, then oral antibiotics to complete 10-14 days total 2, 4

Important Considerations

• Avoid fluoroquinolones during pregnancy due to potential fetal risks 1
• Avoid trimethoprim-sulfamethoxazole in first trimester (folate antagonism) and near term (kernicterus risk) 1
• Avoid aminoglycosides when possible due to nephrotoxicity and ototoxicity risks 1
• Rising antimicrobial resistance is a major concern, particularly ESBL-producing E. coli (47%) and Klebsiella (36.9%) 6
• E. coli remains the most common pathogen in pregnancy UTIs (approximately 40-42% of cases) 4, 6

Follow-up and Prevention

• Repeat urine culture 7 days after treatment completion to confirm cure 5
• For recurrent UTIs in pregnancy, consider prophylactic antibiotics 4
• Untreated bacteriuria in pregnancy increases risk of pyelonephritis from 1-2% to 20-30% 3
• Treatment of asymptomatic bacteriuria reduces pyelonephritis rates from 20-35% to 1-4% 3

Pitfalls to Avoid

• Don't treat mixed flora in urine culture (indicates contamination) 1
• Don't rely on urinalysis alone for diagnosis (culture is required) 3, 1
• Don't forget to follow up with post-treatment cultures to confirm cure 5
• Don't use empiric antibiotics without considering local resistance patterns 6
• Don't miss screening for asymptomatic bacteriuria, which can lead to pyelonephritis if untreated 3

The treatment of UTIs in pregnancy requires careful antibiotic selection to ensure both maternal cure and fetal safety. The rising prevalence of antimicrobial resistance necessitates culture-guided therapy whenever possible 6.