What is the recommended management of cystitis in pregnancy?

Management of Cystitis in Pregnancy

Obtain a urine culture before initiating antibiotics in any pregnant woman with UTI symptoms, then treat with nitrofurantoin 100 mg twice daily for 5 days (avoiding use after 36 weeks), fosfomycin 3 g single dose, or a third-generation cephalosporin for 3 days. 1

Diagnostic Requirements

Urine culture is mandatory before treatment in pregnancy – unlike non-pregnant women where empiric therapy based on symptoms alone is acceptable, pregnancy fundamentally changes the risk-benefit calculus and requires culture-directed therapy. 1 This approach ensures appropriate drug selection and confirms microbiologic eradication, which is critical given the 20-40% risk of progression to pyelonephritis if bacteriuria is inadequately treated. 2, 3

First-Line Antibiotic Regimens

Nitrofurantoin

• Dose: 100 mg orally twice daily for 5 days. 1
• Critical safety limitation: Must be avoided after 36 weeks gestation due to risk of neonatal hemolytic anemia. 1
• Retains excellent activity against resistant uropathogens including ESBL-producing E. coli. 4

Fosfomycin Trometamol

• Dose: 3 g as a single oral dose. 1
• Offers superior adherence due to single-dose convenience and is safe throughout all trimesters. 1
• Clinical trial data in pregnant women demonstrate 95.2% therapeutic success (clinical cure plus bacteriologic eradication) for acute cystitis. 2
• May have slightly lower cure rates than multi-day regimens but this is offset by perfect adherence. 1

Third-Generation Cephalosporins

• Options: Cefixime or ceftibuten for 3 days. 1
• High susceptibility of E. coli (the causative pathogen in 70-85% of cases) and excellent safety profile throughout pregnancy. 1, 4
• Ceftibuten 400 mg daily for 3 days achieved 90% therapeutic success in pregnant women with acute cystitis. 2

Alternative Agents When First-Line Options Unavailable

• Amoxicillin-clavulanate or cephalexin are acceptable beta-lactam alternatives, though they demonstrate modestly lower efficacy compared to nitrofurantoin or fosfomycin. 1
• Trimethoprim-sulfamethoxazole: Contraindicated in first trimester (neural tube defect risk) and third trimester (kernicterus risk). 1 May be considered in second trimester only if local resistance is <20% and the isolate is susceptible. 1

Treatment Duration and Post-Treatment Monitoring

• Standard duration: 5-7 days for symptomatic cystitis. 1
• Mandatory follow-up: Pregnant patients require periodic urine cultures after therapy to detect recurrent bacteriuria, as up to one-third will experience recurrence. 1, 3
• If symptoms persist beyond 7 days: Obtain repeat urine culture and susceptibility testing before prescribing additional antibiotics. 1

Critical Pitfalls to Avoid

Fluoroquinolones Are Absolutely Contraindicated

• Never use fluoroquinolones in pregnancy due to documented cartilage toxicity in the developing fetus. 1

Do Not Skip Urine Culture

• Even with classic UTI symptoms, culture confirmation is mandatory in pregnancy – this is a fundamental difference from non-pregnant management. 1

Nitrofurantoin Restrictions

• Contraindicated for pyelonephritis due to poor tissue penetration. 1
• Contraindicated after 36 weeks due to neonatal hemolysis risk. 1

Recognize When Hospitalization Is Required

• Acute pyelonephritis requires hospitalization and parenteral therapy with IV amoxicillin + aminoglycoside, ceftriaxone 1-2 g daily, or carbapenems for 10-14 days total duration. 1
• Pyelonephritis in pregnancy carries significant maternal and fetal morbidity including preterm labor, transient renal failure, ARDS, sepsis, and hematologic abnormalities. 3

Asymptomatic Bacteriuria Screening

• All pregnant women should be screened with urine culture at the first prenatal visit. 5, 3
• Untreated asymptomatic bacteriuria places mothers at risk for low birth weight, preterm birth, and progression to pyelonephritis in up to 25% of cases. 5, 3
• A single first-trimester screen-and-treat approach with short-course therapy (beta-lactams, nitrofurantoin, or fosfomycin) is recommended. 1

Algorithm for Antibiotic Selection

1. Obtain urine culture first 1
2. Choose based on trimester and local resistance:
   • First or second trimester: Nitrofurantoin 100 mg BID × 5 days OR fosfomycin 3 g × 1 dose OR cefixime/ceftibuten × 3 days 1
   • After 36 weeks: Fosfomycin 3 g × 1 dose OR third-generation cephalosporin × 3 days (avoid nitrofurantoin) 1
3. Arrange periodic follow-up cultures to detect recurrence 1
4. If symptoms persist or recur within 2 weeks: Repeat culture and switch antibiotic class 1