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Asymptomatic bacteriuria in late pregnancy — MSRA MCQ

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HardUrinary Tract InfectionsAsymptomatic bacteriuria in late pregnancyMSRA

A 28-year-old primigravida at 37+5 weeks’ gestation is reviewed after a midstream urine culture, taken because she reported cloudy urine, grows >10^5 CFU/mL Escherichia coli. She has no dysuria, frequency, suprapubic pain, fever, rigors, loin pain, vomiting or uterine tenderness. Observations are normal and fetal movements are normal. The isolate is susceptible to amoxicillin, cefalexin and nitrofurantoin. Her eGFR is 96 mL/minute/1.73 m² and she has no drug allergies. What is the most appropriate management now?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: D — Prescribe amoxicillin 500 mg three times daily for 7 days

Explanation lettering: B = shown as A · C = shown as B · A = shown as C

This is asymptomatic bacteriuria in pregnancy: the quantitative culture is significant and she has no symptoms of lower or upper UTI. Unlike asymptomatic bacteriuria in most non-pregnant adults, it requires immediate antibiotic treatment in pregnancy because it increases the risk of pyelonephritis and premature delivery. A 7-day course is required for bacteriuria in pregnancy. Although nitrofurantoin is normally a first-choice option when renal function is adequate, NICE advises avoiding it at term because of the risk of neonatal haemolysis. At 37+5 weeks, amoxicillin is the appropriate culture-directed alternative because the organism is susceptible and she has no penicillin allergy. A is inappropriate because observation without treatment is not recommended for asymptomatic bacteriuria during pregnancy. B uses an otherwise suitable duration and antibiotic, but nitrofurantoin should be avoided at term. C gives an inadequate 3-day duration, which applies to uncomplicated lower UTI in non-pregnant women rather than bacteriuria in pregnancy. E is not indicated because there are no symptoms or signs of pyelonephritis, sepsis, inability to take oral treatment or obstetric instability.

Reference: Urinary tract infection (lower): antimicrobial prescribing (NG109), Recommendations (2018) — https://www.nice.org.uk/guidance/ng109/chapter/recommendations Urinary tract infection (lower): antimicrobial prescribing (NG109), Table 2: antibiotics for pregnant women aged 12 years and over (2018) — https://www.nice.org.uk/guidance/ng109/chapter/recommendations Urinary tract infection (lower): antimicrobial prescribing (NG109), Summary of the evidence (2018) — https://www.nice.org.uk/guidance/ng109/chapter/summary-of-the-evidence