What is the recommended treatment for Urinary Tract Infection (UTI) in a woman at 18 months of gestation?

From the Guidelines

For treating a urinary tract infection (UTI) in an 18-month pregnant woman, the first-line treatment is typically an oral antibiotic such as nitrofurantoin (Macrobid) 100mg twice daily for 7 days or cephalexin (Keflex) 500mg four times daily for 7 days, as recommended by the Infectious Diseases Society of America 1.

Key Considerations

• The optimal duration of therapy will be antimicrobial-specific, with nitrofurantoin and β-lactam antimicrobials being preferred due to their safety in pregnant women 1.
• A Cochrane review from 2015 found that 7 days of therapy was more effective than a single dose in preventing the adverse outcome of lower birth weight, but no differences in pyelonephritis or preterm delivery were observed between the 2 study arms 1.
• The American Urological Association (AUA) recommends using first-line therapy, such as nitrofurantoin, trimethoprim-sulfamethoxazole (TMP-SMX), or fosfomycin, dependent on the local antibiogram for the treatment of symptomatic UTIs in women 1.

Treatment Options

• Nitrofurantoin (Macrobid) 100mg twice daily for 7 days
• Cephalexin (Keflex) 500mg four times daily for 7 days
• Amoxicillin-clavulanate (Augmentin) 500mg three times daily for 7 days

Important Notes

• Pregnant women should increase fluid intake to help flush bacteria from the urinary tract and urinate frequently to avoid urine stasis.
• Untreated UTIs during pregnancy can lead to serious complications, including pyelonephritis (kidney infection), preterm labor, and low birth weight, making prompt treatment crucial.
• After treatment, a follow-up urine culture is recommended to ensure the infection has cleared completely.
• Some antibiotics commonly used for UTIs in non-pregnant patients, such as fluoroquinolones and tetracyclines, should be avoided during pregnancy due to potential risks to the developing fetus.

From the FDA Drug Label

nitrofurantoin (macrocrystals) The FDA drug label does not answer the question.

From the Research

UTI Treatment in Pregnancy

• The treatment of urinary tract infections (UTIs) in pregnant women is crucial to prevent complications for both the mother and the fetus 2, 3.
• According to a study published in 1994, single-dose cure rates with amoxicillin are approximately 80 percent, while trimethoprim/sulfamethoxazole provides cure rates of greater than 80 percent 2.
• The same study recommends separating pregnant subjects with UTI into two groups: those with asymptomatic bacteriuria can be treated with a single dose of an antimicrobial to which the organism is susceptible, and those with symptomatic UTI can be treated with amoxicillin 500 mg tid for three days 2.
• A 2022 literature review of international guidelines for UTI treatment in pregnancy found concordance between guidelines regarding several aspects of antibiotic treatment, but also areas of discordance, such as antenatal screening for bacteriuria and the use of fluoroquinolones 3.
• A 2020 study on the treatment of UTIs in the era of antimicrobial resistance and new antimicrobial agents recommends using nitrofurantoin, fosfomycin, or pivmecillinam as first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females, but notes that high rates of resistance preclude the use of trimethoprim-sulfamethoxazole and ciprofloxacin in several communities 4.
• A 2011 Cochrane review of treatments for symptomatic UTIs during pregnancy found that all the antibiotics studied were effective in decreasing the incidence of different outcomes, but there were insufficient data to recommend any specific drug regimen for treatment of symptomatic UTIs during pregnancy 5.
• A 2006 study on diagnostic tests versus bacteriological culture for UTIs in general practice patients found that a positive nitrite test or a negative nitrite test with a positive leucocyte-esterase test confirmed UTI, while a negative nitrite together with a negative leucocyte-esterase test did not rule out infection 6.

Antibiotic Options

• Amoxicillin: single-dose cure rates of approximately 80 percent 2.
• Trimethoprim/sulfamethoxazole: cure rates of greater than 80 percent 2.
• Nitrofurantoin: recommended as first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females 4.
• Fosfomycin: recommended as first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females 4.
• Pivmecillinam: recommended as first-line empiric antibiotic therapy for acute uncomplicated bacterial cystitis in otherwise healthy adult nonpregnant females 4.

Considerations for Pregnant Women

• UTIs in pregnancy can lead to significant maternal and neonatal morbidity and mortality 5.
• Antibiotic treatment is effective for the cure of UTIs, but there are insufficient data to recommend any specific drug regimen for treatment of symptomatic UTIs during pregnancy 5.
• The choice of antibiotic should take into account the susceptibility of the uropathogen and the potential risks and benefits to the mother and fetus 2, 3.