Vaginal microbiome exposure for newborns delivered by C-section

Vaginal Microbiome Seeding and Health Outcomes in Cesarean-delivered Neonates: a Randomized Controlled Trial

Phase1; Phase2 Interventional National Institute of Allergy and Infectious Diseases (NIAID) · NCT03298334

This study is testing if exposing newborns delivered by C-section to their mother’s vaginal bacteria can improve their health and development over the first three years of life.

Quick facts

PhasePhase1; Phase2
Study typeInterventional
Enrollment600 (estimated)
Ages0 Days to 50 Years
SexAll
SponsorNational Institute of Allergy and Infectious Diseases (NIAID) NIH
Locations1 site (Falls Church, Virginia)
Trial IDNCT03298334 on ClinicalTrials.gov

What this trial studies

This clinical trial investigates the effects of vaginal microbiome seeding on health outcomes in newborns delivered via scheduled Cesarean section. Infants will be randomly assigned to receive either exposure to their mother's vaginal flora or a sham treatment at birth. The study aims to assess the impact of this intervention on the development of the gut microbiome, immune function, and metabolic outcomes over a three-year period. The trial is divided into two phases, with the first phase focusing on microbiota composition and the second phase evaluating body mass index and immune-mediated outcomes in a larger cohort.

Who should consider this trial

Good fit: Ideal candidates include mothers scheduled for Cesarean delivery at 37 weeks or later, in good health, and with a Lactobacillus-dominated vaginal microbiota.

Not a fit: Patients who may not benefit include those with complications during pregnancy or those who do not meet the strict eligibility criteria for maternal health and microbiota status.

Why it matters

Potential benefit: If successful, this approach could reduce the risk of obesity and immune disorders in Cesarean-delivered infants by restoring beneficial maternal microbes.

How similar studies have performed: Previous pilot studies have shown promising results in normalizing microbiota through vaginal seeding, suggesting potential for success in this larger trial.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria for Mother:

* Scheduled for cesarean delivery at ≥ 37 weeks
* Pregnant with single fetus, in good general health, age 18 years or older
* Negative maternal testing for infections transmitted through vaginal and/or other body fluids performed as standard of care tests in early pregnancy
* Negative testing for Group B strep at 35-37 weeks gestation
* Vaginal pH ≤ 4.5 indicative of Lactobacillus-dominated vaginal microbiota
* No maternal or fetal complications that may inhibit the ability to perform microbiome restoration per protocol
* English or Spanish speaking
* Negative maternal testing for Gonorrhea, Chlamydia, Hepatitis B, Hepatitis C, Syphilis, and HIV at 35 weeks gestation or later
* Women aged 18-29 years must have a normal Pap test within 3 years
* Women aged 30-65 years must have a normal Pap test and an HPV test (co-testing) within 5 years or FDA-approved primary hrHPV testing alone within 5 years or a normal Pap test alone within 3 years
* Negative maternal testing for SARS-CoV-2 for the delivery admission performed as standard of care test at the Inova Health System.

Inclusion Criteria for Infant:

* Infant condition after delivery requires no more than standard neonatal resuscitation\* or is otherwise medically unable to receive the full VMT procedure

\[\*\] Standard neonatal resuscitation may include: tactile stimulation, bulb suction, oxygen without positive pressure, or drying

Exclusion Criteria for Mother:

* Delivery at a hospital other than Inova Health System
* Cesarean delivery scheduled for active infection that would have interfered with vaginal delivery such as genital herpetic lesions
* Rupture of membranes prior to scheduled cesarean delivery
* Bacterial vaginosis within 30 days of cesarean delivery
* Symptomatic urinary tract infection within 30 days of cesarean delivery
* Antibiotic therapy within 30 days of cesarean delivery (exclusive of medication use for prophylaxis at the time of surgery)
* Symptoms on admission suggesting Chorioamnionitis, e.g. maternal fever, fundal tenderness
* Symptoms on delivery admission of possible vaginal infection such as genital herpetic lesions
* History of genital HSV
* History positive testing for Group B strep infection
* History of a child with a diagnosis of Group B strep sepsis
* Pregnancy a result of donor egg or surrogacy
* Preexisting history of Type I or Type II Diabetes
* Maternal history of documented genital HPV infection, positive HPV testing or genital warts on physician examination
* Positive maternal testing for SARS-CoV-2 within 30 days of delivery or symptoms on admission suggesting potential Covid-19 infection

Where this trial is running

Falls Church, Virginia

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Cesarean Delivery Affecting NewbornObesity, ChildhoodIntestinal MicrobiomeMicrobiotaHost Microbial InteractionsGastrointestinal Microbiome
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.