We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (March 2010) and reference lists of retrieved studies.
SELECTION CRITERIA: Review authors independently screened the studies for inclusion and extracted data.
MAIN RESULTS: We included five studies involving 1140 women with asymptomatic
bacteriuria. We did not perform meta-analysis; each trial examined different
antibiotic regimens and so we were not able to pool results. In a study comparing a single dose of
fosfomycin trometamol 3 g with a five-day course of
cefuroxime, there was no significant difference in
persistent infection (risk ratio (RR) 1.36, 95% confidence interval (CI) 0.24 to 7.75), shift to other
antibiotics (RR 0.08, 95% CI 0.00 to 1.45), or in
allergy or
pruritus (RR 2.73, 95% CI 0.11 to 65.24). A comparison of seven-day courses of 400 mg
pivmecillinam versus 500 mg
ampicillin, both given four times daily, showed no significant difference in
persistent infection at two weeks or
recurrent infection, but there was an increase in
vomiting (RR 4.57, 95% CI 1.40 to 14.90) and women were more likely to stop treatment early with
pivmecillinam (RR 8.82, 95% CI 1.16 to 66.95). When
cephalexin 1 g versus
Miraxid(R) (
pivmecillinam 200 mg and
pivampicillin 250 mg) were given twice-daily for three days, there was no significant difference in persistent or
recurrent infection. A one- versus seven-day course of
nitrofurantoin resulted in more
persistent infection with the shorter course (RR 1.76, 95% CI 1.29 to 2.40), but no significant difference in symptomatic
infection at two weeks,
nausea, or
preterm birth. Comparing
cycloserine with sulphadimidine, no significant differences in symptomatic, persistent, or
recurrent infections were noted.
AUTHORS' CONCLUSIONS: We cannot draw any definite conclusion on the most effective and safest
antibiotic regimen for the initial treatment of asymptomatic
bacteriuria in pregnancy. One study showed advantages with a longer course of
nitrofurantoin, and another showed better tolerability with
ampicillin compared with
pivmecillinam; otherwise, there was no significant difference demonstrated between groups treated with different
antibiotics. Given this lack of conclusive evidence, it may be useful for clinicians to consider factors such as cost, local availability and side effects in the selection of the best treatment option.