Vaginal Microbiome Exposure and Immune Responses in C-section Infants

This is a pilot study of 120 pregnant women and their infants conducted at hospitals in the Mount Sinai Health System in New York, NY. Eighty women will deliver via elective, unlabored C‐section, and 40 will undergo spontaneous vaginal delivery. The 80 women undergoing C‐section will be randomized in a masked (blinded) 1:1 fashion to have their neonates undergo vaginal seeding or placebo seeding immediately after birth (within 5 minutes) followed by standard care.The infants of the 40 women undergoing spontaneous vaginal delivery will receive usual standard care. All 120 pregnant women will have biospecimens collected to assess their vaginal, skin, gut, placental, breast milk, and oral microbiome. All infants will have biospecimens collected to assess their gut, skin, nasal, and oral microbiome, as well as blood to assess allergen sensitization and immune markers. Infants will be followed with at‐home stool collections and questionnaires weekly for the first 4 weeks and at weeks 8, 26, and 39. An in‐person study visit will occur at 13 weeks and 52 weeks, and the primary endpoint will be assessed at 52 weeks. Study enrollment is projected to occur over 24 months.