Antibiotics for asymptomatic bacteriuria and cystitis in pregnancy

Antibiotic	Dose	Duration	Notes
Nitrofurantoin	100 mg orally every 12 hours	5 to 7 days	Does not achieve therapeutic levels in the kidneys, so should not be used if pyelonephritis is suspected. Typically avoided during the first trimester and at term; however, it is an appropriate alternative during these periods when other options cannot be used.
Amoxicillin	500 mg orally every 8 hours or 875 mg orally every 12 hours	5 to 7 days	Resistance may limit its utility among gram-negative pathogens.
Amoxicillin-clavulanate	500 mg orally every 8 hours or 875 mg orally every 12 hours	5 to 7 days
Cephalexin	250 to 500 mg orally every 6 hours	5 to 7 days
Cefpodoxime	100 mg orally every 12 hours	5 to 7 days
Fosfomycin	3 g orally as single dose		Does not achieve therapeutic levels in the kidneys so should not be used if pyelonephritis is suspected.
Trimethoprim-sulfamethoxazole	800/160 mg (1 double-strength tablet) every 12 hours	3 days	Typically avoided during the first trimester and at term; however, it is an appropriate alternative during these periods when other options cannot be used.

The durations listed in the table are based on data from studies conducted in both nonpregnant and pregnant women.

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