Cesarean section versus vaginal delivery: Early microbiome seeding and later hygiene-related disease risk — a narrative review

Birth is the first and arguably the most consequential microbial exposure of a human life. During vaginal delivery, the newborn passes through the birth canal and is inoculated with maternal vaginal and perineal microbiota dominated by Lactobacillus, Prevotella, and Bacteroides species; infants born by cesarean section (C-section) bypass this inoculum and are instead colonized mainly by skin and operating-room associated organisms such as Staphylococcus and Corynebacterium.