Babies born through vaginal delivery have different gut bacteria than those delivered by Caesarean, a new study reports. Scientists from the Wellcome Sanger Institute, UCL (University College London), the University of Birmingham, and their collaborators discovered that vaginally-born babies seem to receive most of their gut bacteria from their mother, and specifically from her gut, while babies born via caesarean have more gut bacteria associated with hospital environments.
Published in Nature today (18th Sept), this is the largest ever study[insert link] of neonatal microbiomes and it calls into question the controversial practice of swabbing babies born via caesarean with the mother’s vaginal bacteria, which seems futile in the face of this new evidence.
The study of microbiomes is still in very early stages, and it remains unclear whether the type of gut bacteria present during infancy have any effect on later health. These researchers found that gut bacteria differences between vaginally born and caesarean delivered babies largely evened out the age of one, but larger follow-up studies are needed to determine how gut bacteria relate to health outcomes. Experts from the Royal College of Obstetricians and Gynaecologists emphasize that these findings should not deter women from having a caesarean birth.
Trevor Lawley, Ph.D., a senior author on the paper from the Wellcome Sanger Institute, said: “This is the largest genomic investigation of newborn babies’ microbiomes to date. We discovered that the mode of delivery had a great impact on the gut bacteria of newborn babies, with transmission of bacteria from mother to baby occurring during vaginal birth. Further understanding of which species of bacteria help create a healthy baby microbiome could enable us to create bacterial therapies.”
To understand more about the development of the microbiome, and if the delivery method affected this process, 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 genomic analysis, the researchers determined which bacteria were present and found a significant difference between the two delivery methods. Vaginally delivered babies had many more health-associated (commensal) bacteria from their mothers, than babies who were born by caesarean.
Principal Investigator of the Baby Biome Study, professor Peter Brocklehurst, of the University of Birmingham, said: “The first weeks of life are a critical window of development of the baby’s immune system, but we know very little about it. We urgently need to follow up this study, looking at these babies as they grow to see if early differences in the microbiome lead to any health issues. Further studies will help us understand the role of gut bacteria in early life and could help us develop therapeutics to create a healthy microbiome.” The Baby Biome Studyis a large-scale UK birth cohort study and biobank, with longitudinal follow-up through electronic health data linkage.