The purpose of a systematic review was to evaluate the information on the impact of synbiotics, probiotics, and prebiotics on intestinal microbiota composition of term newborns delivered through cesarean section (C-section) or subjected to antibiotics in 1st week of life.

A comprehensive systematic search was done using databases like Embase and Medline. Critical appraisal, full-text screening (n = 46), and title and abstract screening (n = 12,230) were all carried out separately by two researchers. Those randomised trials were encompassed that comprised term-born children who were born through C-section or who were given postpartum antibiotics in 1st week of life,  pre-, pro-, or synbiotics were given less than six weeks after birth, and the outcome(s) consisted of microbiota analyses.

Overall, 12 randomized controlled studies examining children delivered by C-section and 1 randomized controlled study involving children given antibiotics were incorporated. A total of 1193 newborns were divided into groups ranging in size from 11 to 230. Supplementation with probiotics (n = 7) or synbiotics (n = 3) considerably raised the number of supplemented bacterial species (of the Bifidobacterium and Lactobacillus genera) and decreased Enterobacteriaceae, notably in those under 4 weeks of age.

Actinobacteria (2 studies), Proteobacteria (1 study), and Firmicutes (1 study) all showed an increase at the phylum level following probiotic administration. Three studies on prebiotics revealed a substantial rise in Bifidobacteria in two of the trials, and an increase in Enterobacteriaceae in one of the studies.

Supplementing synbiotics, probiotics, and prebiotics tended to increase the genera, families, phyla, and species that corresponded to synbiotic or probiotic intervention. However, the benefits of a prebiotic were not statistically significant in infants who were delivered by C-section or children who got antibiotics early in life.