Infant Delivery Method Linked to Gut Bacteria

A new study published today in the journal JAMA Pediatrics reports that the gut bacteria of 6-week-old babies might be related to the way the infants were delivered and to what they have been eating.


There was a different composition of gut bacteria in babies who were delivered vaginally than in those delivered by cesarean section, and babies who were fed breast milk exclusively since birth also had a different gut bacteria composition than those who were fed with breast milk and formula. The study looked at 102 babies, 70 who were vaginally delivered and 32 delivered by c-section. Of this group, 70 were given only breast milk in their first six weeks, 26 were fed both breast milk and formula, and 6 fed on only formula.

Study co-author Dr. Juliette Madan, a neonatologist at Children’s Hospital at Dartmouth-Hitchcock in Lebanon, New Hampshire says that the babies delivered via c-section had elevated levels of bacteria from the group Staphylococcus. Some species of bacteria in this group have been associated with disease, although for this study the research team did not investigate whether specific bacteria found was associated with the disease.

Continuing to look at the composition of gut bacteria in infants, the team also found that the bacteria Lactococcus was present more frequently in babies who were exclusively fed formula than in those who only received breast milk. It’s still unclear if this type of bacteria plays any role in human health.

The research did not examine if these differences in the composition of gut bacteria translate into health outcomes for the babies in the study, but they hope their findings will allow scientists to better understand how the microbiome works in training the human immune system.

Dr. Mardan believes this research is just a start, and will lead to further studies to find out how gut bacteria relates to health outcomes.


About the author


Vicki Clinebell is a former television advertising executive who spent 25+ years with an ABC television affiliate in sales and marketing. A journalism major in college at the University of Colorado/Boulder, she now writes for a variety of online and print publications and provides blog content for clients including retail businesses and artists. The diversity of subject matter appeals to her, whether she’s reporting on the latest trends in baby gear, highlighting stories about outdoor adventures, or explaining basic pet-care tips. Even better, she says, is the shorter work commute… just down the hall, and a dress code that’s changed from suits and heels to jeans and a sweatshirt.

1 Comment

  • I would love to know about the gut bacteria axis with a C-section delivery and then if the baby is breastfed exclusively vs. vaginal and breastfed only because my son was an emergency C-section but he was breastfed for 14 months, no formula. Sometimes we can’t control the birthing process but we are able to feed them naturally.

Leave a Comment