Antibiotics for asymptomatic bacteriuria in pregnancy.
BACKGROUND
Asymptomatic bacteriuria occurs in 2% to 10% of pregnancies and, if not treated, up to 30% of mothers will develop acute pyelonephritis. Asymptomatic bacteriuria has been associated with low birthweight and preterm delivery.


OBJECTIVE
To assess the effect of antibiotic treatment for asymptomatic bacteriuria on persistent bacteriuria during pregnancy, the development of pyelonephritis and the risk of low birthweight and preterm delivery.


METHODS
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2007).


METHODS
Randomized trials comparing antibiotic treatment with placebo or no treatment in pregnant women with asymptomatic bacteriuria found on antenatal screening.


METHODS
We assessed trial quality.


RESULTS
Fourteen studies were included. Overall the study quality was poor. Antibiotic treatment compared to placebo or no treatment was effective in clearing asymptomatic bacteriuria (risk ratio (RR) 0.25, 95% confidence interval (CI) 0.14 to 0.48). The incidence of pyelonephritis was reduced (RR 0.23, 95% CI 0.13 to 0.41). Antibiotic treatment was also associated with a reduction in the incidence of low birthweight babies (RR 0.66, 95% CI 0.49 to 0.89) but a difference in preterm delivery was not seen.


CONCLUSIONS
Antibiotic treatment is effective in reducing the risk of pyelonephritis in pregnancy. A reduction in low birthweight is consistent with current theories about the role of infection in adverse pregnancy outcomes, but this association should be interpreted with caution given the poor quality of the included studies.
Smaill
F
F
McMaster University, Department of Pathology and Molecular Medicine, Faculty of Health Sciences, Room 2N16, 1200 Main Street West, Hamilton, Ontario, Canada L8N 3Z5. smaill@mcmaster.ca
Vazquez
J C
JC
D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001437:Bacteriuria / Q000150:complications / Q000188:drug therapy*; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D016017:Odds Ratio; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy*; D011704:Pyelonephritis / Q000209:etiology; D016032:Randomized Controlled Trials as Topic
D000900:Anti-Bacterial Agents