Recommended Antibiotics for UTI During First Trimester of Pregnancy
Nitrofurantoin is the recommended first-line antibiotic for urinary tract infections during the first trimester of pregnancy, with fosfomycin as an acceptable alternative. 1, 2
First-Line Options
- Nitrofurantoin (100 mg twice daily for 5 days) is safe and effective during the first trimester, with high efficacy against common uropathogens like E. coli 2, 3
- Fosfomycin trometamol (3 g single dose) offers the advantage of one-time dosing with similar efficacy to nitrofurantoin and is safe during pregnancy 3, 4
Second-Line Options
- Cephalosporins (e.g., cefixime) can be used when first-line agents are not appropriate due to resistance patterns or allergies 2, 5
- Amoxicillin-clavulanate may be considered based on local susceptibility patterns 3, 5
Antibiotics to Avoid in First Trimester
- Trimethoprim should NOT be used during the first trimester of pregnancy 1
- Trimethoprim-sulfamethoxazole should be avoided during the first trimester 1
- Fluoroquinolones should be avoided throughout pregnancy due to potential adverse effects 1, 5
Important Considerations
- A urine culture is always recommended for pregnant women with suspected UTI before initiating treatment 1
- Treatment duration should be 5 days for nitrofurantoin and single dose for fosfomycin 1, 4
- Antibiotic choice should be guided by local resistance patterns and patient-specific factors such as allergies 1
- Post-treatment urine culture is not routinely indicated for asymptomatic patients after completing therapy 1
Special Situations
- For recurrent UTIs in pregnancy, postcoital prophylaxis with nitrofurantoin (50 mg) or cephalexin (250 mg) as a single dose after intercourse has shown significant effectiveness 6
- For pyelonephritis during pregnancy, hospitalization and parenteral antibiotics are typically required (cephalosporins or amoxicillin with aminoglycosides) 3
Pitfalls to Avoid
- Do not use trimethoprim or trimethoprim-sulfamethoxazole in the first trimester due to potential teratogenic effects 1
- Do not rely on dipstick testing alone for diagnosis in pregnant women; urine culture is essential 1
- Do not delay treatment in pregnant women with symptomatic UTI as it increases risk of pyelonephritis and adverse pregnancy outcomes 1
- Do not use nitrofurantoin in women with G6PD deficiency or at term (38-42 weeks) due to risk of hemolytic anemia in the newborn 3