Mode of delivery, independent of maternal antibiotic exposure, plays a major role in infant gut microbiota development, according to results of a study presented at the 29th European Congress of Clinical Microbiology & Infectious Diseases, held April 13-16, 2019, in Amsterdam, The Netherlands.

It is becoming increasingly clear that the human microbiome has an effect on health, as evidence of microbial community perturbations have been associated with various disorders. It has been suggested that early life microbiota development may be influenced by mode of delivery, but it is unclear whether this influence may be a result of maternal antibiotic exposure during labor and delivery. Therefore, this prospective birth cohort study assessed the independent effects of mode of delivery on infant gut microbiota development and health outcome in the first year of life.

In total, 46 infants delivered by caesarean section and 74 vaginally delivered infants were included in the study. Mothers who underwent caesarean section delivery had antibiotic administration postponed until after cord clamping. Within the first year of life, feces were collected from infants 10 times. Feces from mothers were also collected 2 weeks after delivery. Microbiota were characterized using 16S rRNA-based sequencing.

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There were significant differences between the delivery mode groups in fecal microbiota composition (P <.001). Fecal seeding from mother to child was observed in vaginally delivered infants (P =.025) but not in infants delivered by caesarean section (P =.271), and this difference was independent of the antibiotics administered to mothers in the caesarean section group since overall gut microbiota between the mothers in each group did not differ (P =.339). The infants who were delivered by caesarean section had less stable microbiota and the acquisition of health-associated Bifidobacterium spp was delayed. This was independent of feeding type, antibiotic use, and hospital stay duration after birth.

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Overall, the study authors concluded that, “Mode of delivery affects the developing infant gut microbiota, independent of maternal peripartum antibiotics.”


Reyman M, Van Houten M, Bosch A, et al. Impact of delivery mode-associated gut microbiota dynamics on health in the first year of life. Presented at: 29th European Congress of Clinical Microbiology & Infectious Diseases, April 13-16, 2019, Amsterdam, The Netherlands. Abstract 6550.