The overarching goal of this project is to compare the microbiome profiles of healthy pregnant women, both before and after the introduction of a probiotic supplement into the maternal diet. Specifically, the investigators are performing a pilot randomized double-blinded placebo-controlled trial, comparing the microbiome profiles of 40 healthy pregnant women randomized to receive an oral probiotic containing a mixture of Lactobacillus and Bifidobacterium species (20 mothers) versus an oral placebo (20 mothers) during the first/second trimester of pregnancy. For each mother, the investigators will collect biospecimens from the vagina, rectum, and urine, both before intervention, and 4-6 weeks after intervention. These biospecimens will be analyzed to obtain their microbiome profiles using next-generation sequencing. The primary outcome of interest is the vaginal microbiome, with secondary outcomes including the microbiomes of the rectum and urine. Additionally, the investigators will collect clinical data from the mother's and infant's medical records to correlate our findings with pregnancy and postnatal outcomes.

Inclusion Criteria:

• Pregnant patients ≥ 18 years of age
• Singleton pregnancy
• Gestational age 6 weeks and 0 days through gestational age 13 weeks and 6 days

Exclusion Criteria:

• Pregnant patients <18 years of age
• Multiple gestations
• Gestational age less than or equal to 5 weeks and 6 days
• Gestational age greater than or equal to 14 weeks and 0 days
• Institutionalization for psychiatric disorder, mental retardation, or criminal activity
• Inability to provide informed consent
• Major medical complication of pregnancy, including but not limited to: Diabetes, Chronic hypertension, Severe obesity with body mass index greater than or equal to 40 kg/m2
• Major surgical complications of pregnancy, including but not limited to: History of Bariatric surgery
• Major obstetrical complication of pregnancy, including but not limited to: History of spontaneous preterm birth
• Known maternal or fetal chromosomal abnormality
• Major fetal anomaly
• Intrauterine fetal demise
• Human immunodeficiency virus (HIV) or Hepatitis
• Chronic immunosuppressive medications or steroids
• Current use of probiotic supplementation
• Active urinary or vaginal infection
• Current use of antibiotics
• Current use of vaginal medication (e.g. vaginal progesterone)
• Cerclage in place