Association Between the Mode of Delivery and Infant Gut Microbiota Composition Up to 6 Months of Age: A Systematic Literature Review Considering the Role of Breastfeeding

Context: Cesarean section (CS), breastfeeding, and geographic location can influence the infant microbiota. Objective: In this systematic review, evidence of the association between mode of delivery and infant gut microbiota up to 6 months of age was evaluated, as was the role of breastfeeding in this association, according to PRISMA guidelines. Data Source: The Pubmed, Web of Science, Scopus, Embase, Medical Database, and Open Grey databases were searched. Data Extraction: A total of 31 observational studies with >2 infant stool collections up to the sixth month of age and a comparison of gut microbiota between CS and vaginal delivery (VD) were included. Data Analysis: Infants born by CS had a lower abundance of Bifidobacterium and Bacteroides spp. at almost all points up to age 6 months. Populations of Lactobacillus, Bifidobacterium longum, Bifidobacterium catenulatum, and Escherichia coli were reduced in infants delivered by CS. Infants born by CS and exclusively breastfed had greater similarity with the microbiota of infants born by VD. Conclusions: Species of Bifidobacterium and Bacteroides are potentially reduced in infants born by CS. Geographic location influenced bacterial colonization.