Duration of treatment for asymptomatic bacteriuria during pregnancy

A Cochrane systematic review has shown that drug treatment of asymptomatic bacteriuria in pregnant women substantially decreases the risk of pyelonephritis and reduces the risk of preterm delivery. However, it is not clear whether single dose therapy is as effective as longer conventional antibiotic treatment.

The objective of this review was to assess the effects of different durations of treatment for asymptomatic bacteriuria in pregnancy.

We searched the Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled Trials Register and the reference lists of articles.

Randomised and quasi-randomised trials comparing antimicrobial therapeutic regimens that differed in duration (particularly comparing single dose with longer duration regimens) in pregnant women diagnosed with asymptomatic bacteriuria.

Trial quality was assessed and data were extracted independently by the reviewers.

Eight studies involving over 400 women were included. All were comparisons of single dose treatment with four to seven day treatments. The trials were generally of poor quality. No difference in 'no-cure' rate was detected between single dose and short course (4-7 day) treatment for asymptomatic bacteriuria in pregnant women (relative risk 1.13, 95% confidence interval 0.82 to 1.54) as well as in the recurrent asymptomtic bacteriuria (relative risk 1.08, 95% confidence interval 0.70 to 1.66). However these results showed significant heterogeneity. No differences were detected for preterm births and pyelonephritis although sample size of trials was small. Longer duration treatment was associated with an increase in reports of adverse effects (relative risk 0.53, 95% confidence interval 0.31 to 0.91).

There is not enough evidence to evaluate whether single dose or longer duration doses are more effective in treating asymptomatic bacteriuria in pregnant women. Because single dose has lower cost and increases compliance, this comparison should be explored in a properly sized randomized controlled trial.