One-day compared with 7-day nitrofurantoin for asymptomatic bacteriuria in pregnancy: a randomized controlled trial

Obstet Gynecol. 2009 Feb;113(2 Pt 1):339-45. doi: 10.1097/AOG.0b013e318195c2a2.


Objective: To evaluate whether a 1-day nitrofurantoin regimen is as effective as a 7-day regimen in eradicating asymptomatic bacteriuria during pregnancy.

Methods: A multicenter, double-blind, randomized, placebo controlled noninferiority trial was conducted in antenatal clinics in Thailand, the Philippines, Vietnam, and Argentina. Pregnant women seeking antenatal care between March 2004 and March 2007 who met the inclusion and exclusion criteria were invited to participate in the study. Those who consented were randomly allocated to receive either a 1-day or a 7-day course of 100 mg capsules of nitrofurantoin, which was taken twice daily. The primary outcome was bacteriologic cure on day 14 of treatment.

Results: : A total of 1,248 of 24,430 eligible women had asymptomatic bacteriuria, making the overall prevalence of 5.1%. Of these 1,248 women, 778 women were successfully recruited, and 386 and 392 women were randomly allocated to 1-day and 7-day regimens, respectively. Escherichia coli was the most common potentially pathogenic bacteria detected, its prevalence approaching 50%. Bacteriologic cure rates at treatment day 14 were 75.7% and 86.2% for 1-day and 7-day regimens, respectively. The cure rate difference was -10.5% (95% confidence interval -16.1% to -4.9%). Mean birth weight and mean gestational age at delivery were significantly lower in the 1-day regimen group. There were fewer adverse effects in the 1-day regimen group, but the differences were not statistically significant.

Conclusion: A 1-day regimen of nitrofurantoin is significantly less effective than a 7-day regimen. Women with asymptomatic bacteriuria in pregnancy should receive the standard 7-day regimen.

Clinical trial registration: ISRCTN,, ISRCTN11966080

Level of evidence: I.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-Bacterial Agents / administration & dosage*
  • Anti-Bacterial Agents / adverse effects
  • Bacteriuria / drug therapy*
  • Double-Blind Method
  • Drug Administration Schedule
  • Female
  • Humans
  • Infant, Low Birth Weight
  • Infant, Newborn
  • Nitrofurantoin / administration & dosage*
  • Nitrofurantoin / adverse effects
  • Pregnancy
  • Pregnancy Complications, Infectious / drug therapy*
  • Premature Birth
  • Prenatal Care
  • Prenatal Exposure Delayed Effects
  • World Health Organization
  • Young Adult


  • Anti-Bacterial Agents
  • Nitrofurantoin

Associated data

  • ISRCTN/ISRCTN11966080