What is the recommended treatment for urinary tract infections (UTIs) in pregnancy?

Treatment of Urinary Tract Infections in Pregnancy

For pregnant women with UTIs, the recommended first-line treatments are nitrofurantoin (100 mg twice daily for 5 days) or cephalexin (500 mg four times daily for 5-7 days), as these antibiotics have the best safety profiles during pregnancy while maintaining high efficacy against common uropathogens.

Diagnosis Considerations

• UTIs occur in approximately 8% of pregnant women 1
• Untreated UTIs during pregnancy can lead to serious complications:
  • Pyelonephritis
  • Preterm labor
  • Low birth weight
  • Sepsis

Antibiotic Treatment Options for UTIs in Pregnancy

First-Line Treatments

• Nitrofurantoin:

  • Dosage: 100 mg twice daily
  • Duration: 5 days
  • Advantages: High urinary concentration, low resistance rates
  • Caution: Avoid in third trimester due to risk of hemolytic anemia in the newborn
  • Contraindication: Avoid if CrCl <30 mL/min 2

• Cephalexin:

  • Dosage: 500 mg four times daily
  • Duration: 5-7 days
  • Advantages: Excellent safety profile throughout pregnancy 2

Alternative Options

• Amoxicillin-clavulanate:

  • Dosage: 500/125 mg twice daily
  • Duration: 5-7 days
  • Consider when first-line agents cannot be used 2

• Fosfomycin:

  • Dosage: 3 g single dose
  • Advantages: Convenient single-dose administration
  • Note: Limited data on use in pregnancy, but included in guidelines for short-course treatment 3

Antibiotics to Avoid or Use with Caution

• Trimethoprim-sulfamethoxazole:

  • Avoid in first trimester (risk of neural tube defects)
  • Avoid in third trimester (risk of kernicterus) 2

• Fluoroquinolones (e.g., ciprofloxacin):

  • Contraindicated due to risk of damage to fetal cartilage 2

Duration of Treatment

• For asymptomatic bacteriuria or uncomplicated cystitis: 5-7 days of therapy is recommended 3
• Single-dose therapy is generally less effective than multi-day regimens, except for fosfomycin 3
• The Infectious Diseases Society of America (IDSA) recommends 4-7 days of antimicrobial therapy for pregnant women with asymptomatic bacteriuria 3

Treatment Algorithm

1. Confirm diagnosis:

   • Urine culture should be obtained before starting antibiotics
   • Positive culture: >100,000 CFU/mL of a single uropathogen

2. Select appropriate antibiotic:

   • First-line: Nitrofurantoin or cephalexin
   • Alternative: Amoxicillin-clavulanate or fosfomycin
   • Consider local resistance patterns when selecting therapy

3. Monitor response:

   • Follow-up urine culture 1-2 weeks after treatment completion
   • If symptoms persist or recur, obtain repeat culture and adjust antibiotics based on susceptibility

4. Prevention of recurrence:

   • For women with history of recurrent UTIs during pregnancy, consider prophylaxis
   • Options include postcoital prophylaxis with nitrofurantoin 50 mg or cephalexin 250 mg 4

Special Considerations

Asymptomatic Bacteriuria

• Screen for and treat asymptomatic bacteriuria in pregnant women 3
• Treatment reduces the risk of pyelonephritis, preterm birth, and low birth weight

Recurrent UTIs in Pregnancy

• For women with history of recurrent UTIs, postcoital prophylaxis has been shown to be highly effective 4
• In one study, postcoital prophylaxis with either cephalexin (250 mg) or nitrofurantoin (50 mg) reduced UTI recurrence from 130 infections pre-prophylaxis to only 1 during pregnancy 4

Pyelonephritis

• Requires more aggressive treatment, often initially with parenteral antibiotics
• Consider hospitalization, especially in first and third trimesters
• Common IV options include ceftriaxone until clinical improvement, then transition to oral therapy 2

Common Pitfalls to Avoid

• Failure to obtain follow-up cultures: Always confirm cure with a post-treatment urine culture
• Inadequate treatment duration: Short-course therapy (except fosfomycin) is associated with higher failure rates in pregnancy
• Using contraindicated antibiotics: Avoid fluoroquinolones and tetracyclines throughout pregnancy
• Ignoring asymptomatic bacteriuria: Unlike in non-pregnant women, asymptomatic bacteriuria requires treatment during pregnancy
• Delaying treatment: Prompt treatment is essential to prevent complications

By following these evidence-based recommendations, clinicians can effectively manage UTIs during pregnancy while minimizing risks to both mother and fetus.