What is the appropriate treatment for a pregnant woman with symptomatic cystitis (urinary tract infection)?

Treatment of Symptomatic Urinary Tract Infection in Pregnancy

Pregnant women with symptomatic cystitis should be treated with a short course of antibiotics, with first-line options including nitrofurantoin (100 mg twice daily for 5 days), fosfomycin trometamol (3 g single dose), or a third-generation cephalosporin, always obtaining a urine culture before initiating therapy. 1, 2

Diagnostic Approach

Urine culture is mandatory in all pregnant women with UTI symptoms before starting antibiotics, unlike in non-pregnant women where empiric treatment without culture is acceptable. 1 This is critical because:

• Pregnancy is a complicating factor that requires culture-directed therapy 1
• Untreated or inadequately treated UTI in pregnancy carries significant maternal-fetal risks 3, 4
• Culture results guide appropriate antibiotic selection and confirm eradication 4

First-Line Antibiotic Regimens

Nitrofurantoin

• Dosing: 100 mg orally twice daily for 5 days 1, 2
• Advantages: Minimal resistance, low collateral damage to normal flora, well-studied safety profile in pregnancy 2, 5
• Critical contraindication: Avoid in the last trimester of pregnancy due to risk of neonatal hemolysis 2

Fosfomycin Trometamol

• Dosing: 3 g single oral dose 1
• Advantages: Single-dose convenience improves compliance, effective throughout pregnancy 6
• Evidence: Achieved 95.2% therapeutic success in pregnant women with acute cystitis 6
• Note: May have slightly lower efficacy than multi-day regimens but excellent for compliance 1, 6

Third-Generation Cephalosporins

• Options: Cefixime or ceftibuten 7
• Rationale: High sensitivity of E. coli (the predominant uropathogen), excellent safety profile in pregnancy 7
• Duration: 3-day course 6

Alternative Agents

Beta-lactams (amoxicillin-clavulanate, cephalexin) are acceptable alternatives when first-line agents cannot be used, though they have lower efficacy than preferred options. 1, 2

Trimethoprim-sulfamethoxazole should be avoided in the first trimester (neural tube defect risk) and last trimester (kernicterus risk), but may be used in the second trimester only if local resistance is <20% and the organism is susceptible. 1

Treatment Duration and Follow-Up

• Standard duration: 5-7 days for symptomatic cystitis 1, 7
• Post-treatment culture: Unlike non-pregnant women, pregnant women should undergo periodic screening for recurrent bacteriuria after therapy 8
• If symptoms persist beyond 7 days: Obtain repeat urine culture and antimicrobial susceptibility testing before prescribing additional antibiotics 8, 2

Management of Acute Pyelonephritis in Pregnancy

If the patient presents with fever, flank pain, or systemic symptoms suggesting pyelonephritis:

• Hospitalization is typically required 3
• Parenteral therapy: Amoxicillin plus aminoglycoside, third-generation cephalosporins (ceftriaxone 1-2 g IV daily), or carbapenems 1, 2, 3
• Duration: 10-14 days total, with transition to oral therapy once afebrile and clinically stable 1
• Do NOT use nitrofurantoin for pyelonephritis due to poor tissue penetration 2

Prevention of Recurrent UTI in Pregnancy

For pregnant women with a history of recurrent UTIs:

• Postcoital prophylaxis: Single dose of cephalexin 250 mg or nitrofurantoin 50 mg after intercourse is highly effective 5
• Continuous prophylaxis: Consider daily low-dose nitrofurantoin (avoid in third trimester) or cephalexin for women with multiple recurrences 5, 4
• Long-term prophylaxis is strongly recommended following acute pyelonephritis during pregnancy 6, 5

Critical Pitfalls to Avoid

• Never use fluoroquinolones in pregnancy due to cartilage toxicity concerns in the developing fetus 1, 2
• Avoid nitrofurantoin in the third trimester (after 36 weeks) due to risk of neonatal hemolytic anemia 2
• Do not skip urine culture in pregnant women even with classic symptoms—pregnancy mandates culture confirmation 1
• Do not treat asymptomatic bacteriuria without screening—while screening and treatment of ASB is recommended in pregnancy, recent evidence questions the strength of this association, but a single first-trimester screen-and-treat approach with short-course therapy remains standard 1, 3
• Recognize that 20-40% of untreated asymptomatic bacteriuria progresses to pyelonephritis in pregnancy, justifying the lower threshold for treatment 6, 4