What are the indications for ordering a urinalysis (UA) and initiating therapy in a pregnant female presenting with symptoms of a urinary tract infection (UTI)?

UTI in Pregnancy: When to Order UA and Indications for Therapy

All pregnant women with UTI symptoms should have urinalysis and urine culture obtained before initiating treatment, and unlike non-pregnant women, all forms of bacteriuria in pregnancy—including asymptomatic bacteriuria—require antibiotic treatment due to high risk of maternal and fetal complications. 1, 2, 3, 4

Key Distinction: Pregnancy Changes Everything

The management of UTI in pregnancy fundamentally differs from non-pregnant women because:

• Pregnancy is excluded from standard uncomplicated UTI guidelines - the AUA/CUA/SUFU guidelines explicitly state they do not apply to pregnant women 5
• All bacteriuria requires treatment in pregnancy, including asymptomatic cases, due to 20-40% risk of progression to pyelonephritis with associated preterm delivery and low birth weight 2, 3, 4
• Urine culture is mandatory before treatment in pregnant women, unlike healthy non-pregnant women where empiric treatment based on symptoms alone is acceptable 1, 3

Symptoms of UTI in Pregnancy

Classic symptoms include:

• Dysuria (burning with urination) - the central diagnostic symptom 5
• Urinary frequency and urgency 5
• Suprapubic discomfort 6
• Hematuria 5
• New or worsening incontinence 5

Red flags requiring immediate evaluation for pyelonephritis:

• Fever 5
• Flank pain 5
• Systemic symptoms (nausea, vomiting, malaise) 1

When to Order Urinalysis in Pregnancy

Always Order UA and Culture:

1. Universal screening for asymptomatic bacteriuria - All pregnant women should be screened with urine culture during pregnancy, typically in the first trimester 3, 4

2. Any UTI symptoms - dysuria, frequency, urgency, or suprapubic pain 1, 6

3. Before initiating any antibiotic therapy - unlike non-pregnant women where empiric treatment is acceptable, pregnancy requires culture confirmation 1, 3

4. Follow-up cultures - Repeat urine culture 7 days after completing treatment to document cure 7

Alternative Risk-Based Screening Approach:

Recent evidence suggests selective screening may be appropriate in resource-rich settings for pregnant women with specific risk factors rather than universal screening 2:

• Previous UTI history 2
• Diabetes mellitus 2
• Urinary tract abnormalities 2
• Immunosuppression 2
• History of preterm birth 2

However, this approach requires two positive cultures to confirm persistent ASB before treatment 2

Indications for Antibiotic Therapy in Pregnancy

Treat ALL of the following:

1. Asymptomatic bacteriuria (ASB) - defined as ≥10^5 CFU/mL on culture without symptoms 3, 4

   • This is the critical difference from non-pregnant patients
   • Prevents progression to pyelonephritis in 20-40% of untreated cases 2, 3

2. Acute cystitis - symptomatic lower UTI with positive culture 6, 4

3. Acute pyelonephritis - upper tract infection with fever and flank pain 6, 4

4. Group B Streptococcus bacteriuria - any colony count requires treatment 4

Empiric Treatment Considerations:

For uncomplicated cystitis, consider empiric treatment while awaiting culture if symptoms are classic:

• Dysuria plus frequency without vaginal discharge or irritation 1
• Start antibiotics immediately but ensure culture was obtained first 6

First-line oral antibiotics for uncomplicated UTI in pregnancy:

• Nitrofurantoin (avoid near term due to hemolytic anemia risk) 6, 7
• Fosfomycin trometamol 6
• Amoxicillin 500 mg three times daily for 3 days (if susceptible) 7
• Third-generation cephalosporins (cefixime preferred) 6
• Trimethoprim-sulfamethoxazole (avoid in first trimester and near term) 7

Treatment duration:

• Single-dose therapy achieves ~80% cure rates for ASB 7
• 3-day courses recommended for symptomatic cystitis 7
• 7-14 days for pyelonephritis with parenteral therapy initially 6

Common Pitfalls to Avoid

Do NOT treat pregnant women like non-pregnant women - the "treat symptoms only" approach used in healthy non-pregnant women does not apply 5, 1

Do NOT skip urine culture - even with classic symptoms, culture is mandatory to confirm diagnosis and guide therapy 1, 3

Do NOT ignore asymptomatic bacteriuria - this requires treatment in pregnancy unlike all other patient populations 2, 3, 4

Do NOT forget follow-up cultures - document cure 7 days post-treatment as recurrence rates are high 7

Do NOT use fluoroquinolones - avoid due to fetal safety concerns despite their efficacy 8, 6

Do NOT assume negative culture on antibiotics rules out infection - obtain cultures before starting treatment whenever possible 8

Antibiotic Prophylaxis

Consider suppressive prophylaxis for:

• Recurrent UTI during pregnancy (≥2 episodes) 4
• History of pyelonephritis in current pregnancy 4
• Persistent bacteriuria despite treatment 4

Prophylactic options:

• Nitrofurantoin 50-100 mg daily at bedtime 4
• Cephalexin 250 mg daily 4