Babies’ gut bacteria affected by delivery method, Baby Biome project shows

Published in Nature today (18th Sept), this largest ever study of neonatal microbiomes also revealed that the microbiome of vaginally delivered newborns did not come from the mother’s vaginal bacteria, but from the mother’s gut. This calls into question the controversial practice of swabbing babies born via caesarean with mother’s vaginal bacteria. Understanding how the birth process impacts on the baby’s microbiome will enable future research into bacterial therapies.

To understand more about the development of the microbiome, and if the delivery method affected this, researchers studied 1,679 samples of gut bacteria from nearly 600 healthy babies and 175 mothers. Faecal samples were taken from babies aged four, seven or 21 days old, who had been born in UK hospitals by vaginal delivery or caesarean. Some babies were also followed up later, up to one year of age.

Using DNA sequencing and genomics analysis, the researchers could see which bacteria were present and found there was a significant difference between the two delivery methods. They discovered that vaginally delivered babies had many more health-associated (commensal) bacteria from their mothers, than babies who were born by caesarean.

Read More: Eureka Alert