This is a single-center, parallel-arm, blind, sham-controlled, feasibility randomized controlled trial (RCT) to be conducted in healthy cesarean-born children. Eligible children will be randomized 1:1 to have their nose swabbed with either maternal vaginal secretions or a sterile swab (intervention vs. control group, respectively). The main hypothesis is that conducting an RCT assessing the utility of vaginal seeding in modifying the early-life upper respiratory tract (URT) microbiome of children born by cesarean section (C-section) is feasible and that the intervention is safe.

Eligible children will be randomized 1:1 to have their nose swabbed with either maternal vaginal secretions or a sterile swab (intervention vs. control group, respectively). The procedure will be performed following birth by C-section and immediately after the initial newborn care by the general pediatric team. The mother and child will then receive usual medical care as determined by their health care providers. Follow-up will occur at multiple time points during the child's first 6 months of life. One planned interim analysis to assess the safety of the procedure will be conducted.

The intervention aims to transfer the maternal vaginal microbiome to the nasal cavity of cesarean-born children at birth (i.e., vaginal seeding of the URT). Hence, the intervention simply attempts to replicate the natural exposure to maternal vaginal secretions during vaginal delivery in children born by C-section.

Inclusion Criteria:

For the mother:

• Female 18-40 years of age who is in good general health, is fully able to provide consent to participate in the study, anticipates being available for the duration of the study, and is willing to comply with all study procedures
• Singleton pregnancy
• Completed ≧3 prenatal care visits at Vanderbilt University Medical Center (any facility)
• Having rectovaginal swabs collected at ≧36 weeks of gestation to screen for Group B Streptococcus (GBS) as part of prenatal screening tests
• Having a scheduled (planned or non-emergency) C-section at Vanderbilt University Medical Center (main campus only)
• No intent to relocate outside the middle Tennessee region within 12 months of recruitment

For the child:

• Estimated gestational age ≧37 weeks
• Birth weight ≧2,500 grams

Exclusion Criteria:

For the mother:

• Past medical history of any of the following:

  • Previous child with GBS infection or prior positive GBS testing
  • Hepatitis B, hepatitis C, or human immunodeficiency virus (HIV) infection
  • Genital herpes simplex virus (HSV) infection, genital herpetic lesions, or prior positive genital HSV testing
  • Genital human papilloma virus (HPV) infection, genital HPV lesions, or prior positive genital HPV testing
  • Diabetes type I or type II

• Laboratory evidence during the current pregnancy of any of the following:

  • GBS bacteriuria in urine samples collected at any time (performed as standard of care)
  • GBS colonization in rectovaginal swabs collected at ≧36 weeks of gestation (performed as standard of care)
  • Chlamydia, trichomoniasis, or gonorrhea in urine samples collected at ≧36 weeks of gestation (performed as part of the screening procedures for this study)
  • Hepatitis B, hepatitis C, HIV, or syphilis in blood samples collected at ≧36 weeks of gestation (performed as part of the screening procedures for this study)

• Uncontrolled gestational diabetes

• Any serious obstetric disease (e.g., preeclampsia with severe features, placental abruption or severe bleeding, or thromboembolic disease) as deemed by the PI or co-investigators

• Prior abnormal Pap smear

• C-section scheduled for a genitourinary infection that would have interfered with vaginal delivery (e.g., genital herpetic lesions)

• Lack of available prenatal screening tests

• Use of systemic (i.e., oral, intramuscular, or intravenous) antibiotics in the 4 weeks prior to delivery (except for those being administered as part of the C-section)

• Use of systemic (i.e., oral, intramuscular, or intravenous) immunosuppressive, biologic, or chemotherapeutic agents in the 3 months prior to delivery (except for systemic immunosuppressive agents not being used for their immunosuppressive effects [e.g., prenatal intramuscular beclomethasone for fetal lung maturation])

• Fever (≧100.4°F [38°C]) in the 72 hours prior to delivery

• Symptoms (e.g., dysuria, pruritus, or discharge) suggestive of a genitourinary infection (e.g., bacterial vaginosis, vaginal yeast infection, chorioamnionitis, or urinary tract infection) on the day of delivery

• Symptoms (e.g., pain, tenderness, tingling, burning, itching, or swollen lymph nodes) suggestive of genital HSV infection on the day of delivery

• Other symptoms (e.g., new-onset rhinorrhea, sore throat, cough, body aches, chills, nausea, vomiting, or diarrhea) suggestive of an acute infectious disease on the day of delivery

• Physical exam findings (e.g., fever [≧100.4°F (38°C)] or vesicles, warts, or ulcers in the genital, perineal, or anal region) suggestive of a genitourinary infection on the day of delivery (performed as part of the screening procedures for this study if not performed as standard of care)

• Maternal vaginal pH>4.5 on the day of delivery (performed as part of the screening procedures for this study)

• Need for a switch from a scheduled C-section to an emergency C-section

• Prelabor prolonged rupture of membranes (i.e., ≧18 hours prior to delivery)

• Pregnancy as the result of an assisted reproductive technology or surrogacy

• Participation in another clinical trial that involves an intervention that could impact the quality or interpretation of the study data as deemed by the PI or co-investigators

• Other past or current medical problems that could compromise the safety of participants, interfere with their ability to comply with study requirements, or impact the quality or interpretation of the study data as deemed by the PI or co-investigators

For the child:

• Need for neonatal measures outside routine clinical care (i.e., drying, tactile stimulation, bulb syringe or catheter suction of nose and mouth, or temperature maintenance) in the delivery room
• Transfer to the neonatal intensive care unit immediately after delivery
• Thick particulate meconium noted during delivery
• Physical exam findings (e.g., tachypnea, nasal flaring, retractions, cyanosis, or grunting) suggestive of neonatal acute respiratory distress immediately after delivery (performed as part of the screening procedures for this study)
• Prenatal diagnosis of a serious genetic, respiratory, cardiovascular, or neurological disease
• Prenatal diagnosis of intrauterine growth restriction
• Prenatal diagnosis of a major congenital anomaly (e.g., cleft lip or palate, cystic hygroma, or giant omphalocele)
• Participation in another clinical trial that involves an intervention that could impact the quality or interpretation of the study data as deemed by the PI or co-investigators
• Other past or current medical problems that could compromise the safety of participants, interfere with their ability to comply with study requirements, or impact the quality or interpretation of the study data as deemed by the PI or co-investigators

De-identified next-generation sequencing data generated as part of this study will be deposited into NIH-sponsored or other scientific repositories immediately following a publication. Other de-identified individual participant data (IPD) that underlie the results reported in a manuscript will be shared with other parties upon request beginning 12 months and ending 36 months following a publication. In addition, the study protocol and informed consent documents will be uploaded to clinicaltrials.gov no later than 60 days after the end-of-study visit of the last enrolled participant.

De-identified next-generation sequencing data generated as part of this study will be deposited into NIH-sponsored or other scientific repositories immediately following a publication. Other de-identified IPD that underlie the results reported in a manuscript will be shared with other parties upon request beginning 12 months and ending 36 months following a publication. In addition, the study protocol and informed consent documents will be uploaded to clinicaltrials.gov no later than 60 days after the end-of-study visit of the last enrolled participant.

Individual requests for de-identified IPD sharing from other parties will be evaluated and approved by the PI. For this, the requesting party will need to provide a methodologically sound proposal, obtain approval from their Institutional Review Board, and sing a data sharing agreement. De-identified IPD will be mainly shared for the purpose of conducting a systematic review with meta-analysis, but other studies will be evaluated on a case-by-case basis.

Participants, the principal investigator (PI), co-investigators, data manager, and the lead biostatistician will be blinded to the actual group assignment until all statistical analyses of the data required to meet the primary and co-primary endpoints have occurred. The Data and Safety Monitoring Board will remain unmasked to actual group allocation throughout the pre-specified blinding period.