Duration of treatment for asymptomatic bacteriuria during pregnancy

Background A previous Cochrane systematic review has shown that antibiotic 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. Objectives To assess the effects of different durations of treatment for asymptomatic bacteriuria in pregnancy. Search methods We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2015) and reference lists of identified articles. Selection criteria Randomized and quasi‐randomized trials comparing antimicrobial therapeutic regimens that differed in duration (particularly comparing single dose with longer duration regimens) in pregnant women diagnosed with asymptomatic bacteriuria. Data collection and analysis Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We assessed the quality of the evidence using the GRADE approach. Main results We included 13 studies, involving 1622 women. All were comparisons of single‐dose treatment with short‐course (four‐ to seven‐day) treatments. The risk of bias of trials included in this review was largely unclear, and most trials were at high risk of performance bias. The quality of the evidence was assessed using the GRADE approach. When the any antibiotic agent was used, the 'no cure' rate for asymptomatic bacteriuria in pregnant women was slightly lower for the short‐course treatment over the single‐dose treatment, although there was evidence of statistical heterogeneity (average risk ratio (RR) 1.28, 95% confidence interval (CI) 0.87 to 1.88; women = 1502, studies = 13; I² = 56%; very low quality evidence). Data from only good quality trials also showed better cure rates with short (four‐ to seven‐day) regimens of the same microbial agent (average RR 1.72, 95% CI 1.27 to 2.33; women = 803, studies = two; I² = 0%; high quality evidence). There was no clear difference in the recurrence of asymptomatic bacteriuria rate between treatment and control groups, whether the same or different microbial agents were used (RR 1.13, 95% CI 0.77 to 1.66; 445 women studies = eight; I² = 0%; very low quality evidence). Differences were detected for low birthweight babies, favoring a short course (four‐ to seven‐day treatment) of the same microbial agent, although the data come from a single tri