Comparison of single dose with a five-day course of trimethoprim for asymptomatic (covert) bacteriuria of pregnancy.

Sixty consecutive pregnant women with asymptomatic (covert) bacteriuria detected between 16 and 30 weeks gestation were randomly allocated to treatment with either a single 600 mg dose or a standard five-day course of trimethoprim. Twenty-seven of 30 women were cured with a single dose. Six of these 27 women were reinfected later in the pregnancy. Twenty-four of 30 women treated with a five-day course of trimethoprim were cured, and five became reinfected later in the pregnancy. One women vomited the single dose. There were no detrimental effects on the outcome of the pregnancies. Single dose therapy should be considered as the treatment of choice for asymptomatic bacteriuria in pregnancy.