This study, Asymptomatic Bacteriuria in Pregnancy in Low- and Middle-IncomE Countries (ABLE), is designed as a 2-arm randomized controlled trial (RCT) focused on pregnant individuals and newborn infants. A positive outcome of this study will contribute to global progress toward WHO Sustainable Development Goal Target 3.2 [End preventable deaths of newborns and children under 5 years of age] by examining the potential impact of this practice to reduce the incidence of SVN/SB and the lifelong health consequences associated with SVNs. In addition, the study will further explore the role and potential benefits of antibiotic treatment of AB in the pregnant individual. In total, 1,134 eligible participants, or approximately 162 per research site, will be randomized in the trial by the research teams in each of the seven international sites that, together with their United States of America (US) partners, participate in the Eunice Kennedy Shriver National Institute of Child Health and Human Development's (NICHD's) Global Network for Women's and Children's Health Research (GN).

Inclusion Criteria:

Individuals who meet the following criteria are eligible for randomization:

• Enrolled in GN MNHR

• Established pregnancy ≥12 and ≤20 weeks GA by last menstrual period and/or clinical assessment and/or ultrasonography

• Age: 18 years (or lower limit age eligible*) to 49 years

  * Some sites will be able to include individuals giving birth regardless of age if they are considered an adult or an emancipated minor. However, other sites will require individuals to be at least 18 years of age. The investigators will adhere to local regulations.

• Expressed understanding of study procedures and willingness to complete screening, randomization, study drug administration and follow-up

• Able to provide informed consent

• Presence of a single bacterial isolate (>105 colony forming unit (CFU)/mL) in urine at enrollment

• Intent to remain in study area for at least 42 days PP

Exclusion Criteria:

Individuals who meet any of the following criteria are not eligible for randomization:

• Gestational age <12 weeks or >20 weeks
• Received treatment with any antibiotic within 14 days before screening visit
• Current symptoms of UTI
• History of allergy to nitrofurantoin
• Pregnancy loss / miscarriage prior to randomization
• Currently taking magnesium-containing antacid
• Any illness / condition (e.g., anemia, diabetes, renal disease, pulmonary disease) requiring immediate medical care per site PI assessment
• Enrollment in another trial that per the study MOP will impact this trial