Urinary tract infection and asymptomatic bacteriuria in pregnancy
Why pregnancy is the exception to "don't treat asymptomatic bacteriuria", screening culture at booking, antibiotic choices by trimester (trimethoprim, nitrofurantoin, amoxicillin-clavulanate), group B streptococcus in urine, admitting pyelonephritis, its complications, and prophylaxis.
Tier 1Condition
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Pregnancy is one of two settings where asymptomatic bacteriuria is screened for and treated. The other is before urological procedures that breach the mucosa.
- Screen with a midstream urine culture at the first antenatal visit, by 16 weeks.
- Asymptomatic bacteriuria affects 2 to 10% of pregnancies, about the same as in non-pregnant women. Pregnancy makes progression to pyelonephritis more likely.
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Sources
- Therapeutic Guidelines: Antibiotic (urinary tract infection and bacteriuria in pregnancy)AU/NZTherapeutic Guidelines Ltd, Revised March 2025
- Australian Pregnancy Care Guidelines (asymptomatic bacteriuria screening)AU/NZLiving Evidence for Australian Pregnancy and Postnatal Care, funded by the Australian Government Department of Health, Living guideline, 2024 onwards
- South Australian Perinatal Practice Guideline: urinary tract infection in pregnancyAU/NZSA Health, Version 4, 2021
- Position statement for the investigation and management of sepsis in pregnancyAU/NZSociety of Obstetric Medicine of Australia and New Zealand, 2023
- Clinical practice guideline for the management of asymptomatic bacteriuria: 2019 update by the Infectious Diseases Society of AmericaNicolle LE et al., Clin Infect Dis 2019;68:e83-110, 2019
- Screening for asymptomatic bacteriuria in adults: US Preventive Services Task Force recommendation statementUSPSTF, JAMA 2019;322:1188-94, 2019
- Antibiotics for asymptomatic bacteriuria in pregnancySmaill FM, Vazquez JC. Cochrane Database Syst Rev 2019, 2019
- Maternal and neonatal consequences of treated and untreated asymptomatic bacteriuria in pregnancy: a prospective cohort study with an embedded randomised controlled trialKazemier BM et al., Lancet Infect Dis 2015;15:1324-33, 2015
- Sulfonamides, nitrofurantoin, and risk of birth defects (Committee Opinion No. 717)American College of Obstetricians and Gynecologists, Obstet Gynecol 2017;130:e150-2, 2017
- Serum creatinine in pregnancy: a systematic reviewWiles K, Bramham K, Seed PT, et al. Kidney Int Rep 2019;4(3):408-19, 2019
- Last updated
- 14 November 2026
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