From the Guidelines
Asymptomatic bacteriuria in early pregnancy should be treated with antibiotics to prevent complications such as pyelonephritis and adverse pregnancy outcomes. The recommended approach is to screen pregnant women at their first prenatal visit (typically between 12-16 weeks) with a urine culture, and if positive (defined as >100,000 colony-forming units/mL of a single organism), initiate antibiotic therapy even without symptoms. First-line treatment options include nitrofurantoin 100 mg orally twice daily for 5-7 days, amoxicillin-clavulanate 500/125 mg orally twice daily for 3-7 days, or cephalexin 500 mg orally four times daily for 3-7 days. Fosfomycin 3 g as a single oral dose is another alternative. Trimethoprim-sulfamethoxazole should be avoided in the first trimester due to potential teratogenic effects. The choice of antibiotic should be guided by culture sensitivity results when available. Following treatment, a test of cure with repeat urine culture is recommended 1-2 weeks after completing antibiotics. Treatment is important because approximately 20-40% of untreated asymptomatic bacteriuria cases will progress to pyelonephritis, which increases risks of preterm birth, low birth weight, and maternal complications. Some women may require suppressive antibiotic therapy throughout pregnancy if they experience recurrent infections, as supported by the Infectious Diseases Society of America guidelines 1. The optimal duration of therapy will be antimicrobial-specific, with a trend toward lower rates of clearance of bacteriuria with single-dose regimens compared to short-course (4–7 days) antimicrobials, as noted in a Cochrane review 1. The US Preventive Services Task Force also recommends screening pregnant women for asymptomatic bacteriuria and treating those with positive results to prevent pyelonephritis and other complications 1.
Key considerations for treatment include:
- Screening for asymptomatic bacteriuria at the first prenatal visit
- Initiating antibiotic therapy for positive results
- Choosing antibiotics based on culture sensitivity results
- Avoiding trimethoprim-sulfamethoxazole in the first trimester
- Considering suppressive antibiotic therapy for recurrent infections
- Following up with a test of cure after completing antibiotics.
Overall, the evidence supports the importance of screening and treating asymptomatic bacteriuria in early pregnancy to prevent complications and improve outcomes for both the mother and the baby, as emphasized by the guidelines and reviews from reputable organizations 1.
From the Research
Treatment Guidelines for Asymptomatic Bacteriuria in Early Pregnancy
- The treatment of asymptomatic bacteriuria in pregnant women is recommended to decrease the risk of pyelonephritis and preterm delivery 2, 3.
- A short-course (four- to seven-day) regimen of antibiotics is associated with better cure rates compared to single-dose treatment 2.
- The American College of Obstetricians and Gynecologists (ACOG) and the Infectious Disease Society of America (IDSA) recommend screening for asymptomatic bacteriuria in the first trimester of pregnancy and treating if positive 4.
- Treatment of asymptomatic bacteriuria in pregnant women has been shown to decrease the risk of symptomatic UTI, low birthweight, and preterm delivery 5.
Duration of Treatment
- The optimal duration of treatment for asymptomatic bacteriuria in pregnancy is not well established, but a short-course (four- to seven-day) regimen is recommended until more data become available 2, 3.
- A single-dose regimen of antibiotics may be less effective than a short-course regimen, but more evidence is needed from large trials measuring important outcomes, such as cure rate 2.
Special Considerations
- Women with recurrent bacteriuria require further clarification on management strategies 6.
- Asymptomatic bacteriuria should be treated prior to transurethral resection surgery and in pregnant women, but not in patients with no risk factors, patients with diabetes mellitus, postmenopausal women, elderly institutionalised patients, patients with renal transplants, or patients prior to joint replacement 5.