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Evidence summaries

Antibiotics Vs. No Treatment for Asymptomatic Bacteriuria in Pregnancy

Antibiotic treatmentappears to reduce the risk of pyelonephritis in pregnancy and appears to reduce the incidence of preterm delivery and low birthweight babies compared to placebo or no treatment. Level of evidence: "B"

A Cochrane review [Abstract] 1 included 15 studies with over 2000 women. Antibiotic treatment compared to placebo or no treatment was effective in clearing asymptomatic bacteriuria. The incidence of pyelonephritis, preterm delivery, and low birthweight babies was reduced (table T1). There were very limited data on which to estimate the effect of antibiotics on other infant outcomes, and maternal adverse effects were rarely described.

Antibiotics for asymptomatic bacteriuria in pregnancy

OutcomeRelative effect(95% CI)Risk with no treatmentRisk with antibiotics (95% CI)of participants(studies)Certainty of the evidence
Development of pyelonephritisRR 0.24(0.13 to 0.41)199 per 100048 per 1000(26 to 82)2017(12) Low
Preterm birth< 37 weeksRR 0.34(0.13 to 0.88)174 per 100059 per 1000(23 to 153)327(3) Low
Birthweight < 2500 gRR 0.64(0.45 to 0.93)136 per 100087 per 1000(61 to 126)1437(6) Low

Comment: The quality of evidence was downgraded by severe limitations in study quality (high or unclear risk of bias in most studies).

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References

  • Smaill FM, Vazquez JC. Antibiotics for asymptomatic bacteriuria in pregnancy. Cochrane Database Syst Rev 2019;2019(11):. [PubMed]

Primary/Secondary Keywords