- Method of delivery: when infants are born vaginally, they harbor vaginal microbes that begin to colonize their gut microbiome. However, in infants born via C-section, there is a disruption of transmission of these microbes. Instead, they often are first exposed to skin, not vaginal, microbes. Furthermore, the maternal vaginal microbiome changes during pregnancy, apparently in order to provide the fetus with a specific microbial inoculum at birth.
- Maternal weight: mothers who are obese often have disrupted vaginal microbiomes, which can contribute to the differential infant microbiome development compared with mothers who are not obese.
- Breast feeding and bottle feeding of newborns: breast milk contains certain probiotics that colonize the infant’s gut prebiotics that help nourish these microbes. This combination is usually not present in formula, and aids in the development of a more uniform gut microbiome than that found in formula-fed infants.
- Perinatal antibiotic treatment: if a mother undergoes antibiotic treatment soon before giving birth, the vaginal microbial community could be greatly disrupted. Also, antibiotic treatments could cause a change in uniformity of the breast milk, which could have a differential effect on the development of the infant’s gut microbiome.
Mueller NT, Bakacs E, Combellick J, Grigoryan Z, Dominguez-Bello MG. 2014. The infant microbiome development: mom matters. Trends Mol Med. 21(2): 109–117.