Participant enrollment, informed consent and health history collection

• Samples were collected from ten maternal body sites (that is, vaginal, cervical, buccal and rectal mucosa, blood, urine, chest, dominant palm, antecubital fossa and nares), five types of birth products (that is cord blood, amniotic fluid, placental membranes, placental tissue and umbilical cord) and seven infant body sites (that is, buccal and rectal mucosa, meconium/stool, chest, right palm, nares and respiratory secretions if intubated)
  • ten maternal body sites
    • vaginal, cervical, buccal(구강) and rectal(직장) mucosa(점막), blood, urine, chest, dominant palm(손바닥), antecubital(팔꿈치안쪽) fossa(뼈의 구멍) and nares(콧구멍)
  • five types of birth products
    • cord blood(제대혈), amniotic fluid, placental membranes, placental tissue and umbilical cord(탯줄)
  • seven infant body sites
    • buccal and rectal mucosa, meconium(태변)/stool, chest, right palm, nares and respiratory secretions if intubated

Maternal sampling schedule

• Samples were collected from appropriately consented women at the enrollment visit, longitudinally at each prenatal visit, at triage, at labor and delivery, at discharge (~24–48 h after birth) and at postpartum follow-up visits
• Vaginal & Rectal samples
  • throughout pregnancy and at postpartum follow-up visits
  • not collected at the discharge visit(퇴원)
• buccal samples
  • during a study visit or by self-sampling at all visit types
• Blood samples
  • at select visits by phlebotomists
• Urine samples
  • were longitudinally collected using a clean-catch protocol for a subset of participants.
• Cervical samples
  • during a pelvic exam using a speculum at select visits
• samples from the antecubital fossa and nares
  • longitudinally throughout pregnancy, at discharge visits and at postpartum follow-up visits, but not at triage visits
• At discharge visits, dominant palm and chest (skin) samples were also collected by a research coordinator

Infant sampling schedule

• Samples from neonates (for example, buccal, rectal, meconium/stool, right palm, chest and nares) were collected at birth (~1 h after birth) and at discharge (~24–48 h after birth)
• For infants admitted to the neonatal intensive care unit (NICU), additional samples were collected at days 3 and 7 of life and weekly until discharge from the NICU, or until the infant’s first birthday

16S rRNA taxonomic surveys of the vaginal microbiome

• V1-V3 region
• 2 * 300 bp paired-end reads, at least 50,000 reads per sample