How C-Sections & Breast Milk Affect Baby's Gut

We've all heard that breastfeeding has major benefits for your child—but it turns out, your mode of delivery can have just as big an impact on Baby's gut bacteria.

baby belly_0.jpg Lana K/Shutterstock

You'd do anything to keep your baby healthy—and it turns out, what happens during your child's earliest days can have a strong influence on a certain health issue.

A recent study finds that two surprising factors can have a profound influence on your child's gut health: Breastfeeding and mode of the baby's delivery both have significant—and seemingly equal—power over the microbiomes present in a child's stomach.

"I was always very interested in learning why breastfeeding and breast milk were associated with such profound health benefits," Juliette Madan, M.D., a study author, said of her decision to study this topic. "I was very interested in learning if some of the benefits of breast milk were mediated into the microbiomes in the infant gut."

Both Dr. Madan and Anne Hoen, Ph.D, the study's other author, knew there were other exposures that would shape the microbiomes in a child's stomach, but were surprised to learn how powerful a factor delivery mode was. "Delivery mode has always been something that's been interesting to us as we look at trying to understand patterns in babies."

It makes sense that breast milk could influence a child's internal makeup—after all, children who are fed breast milk are consuming this directly—but how does delivery mode (that is to say, whether the child was born via vaginal birth or C-section) have such a strong pull? "When you look at the vaginal microbiomes of moms who are pregnant...we see that the vaginal microbiome gets very focused. It goes from being relatively diverse to not very diverse with a very large preponderance of lactobacillus, [which is] bugs that we use as a probiotic. This bacteria is critical for infant health: Babies are not really bred to be able to metabolize all the nutrients in milk and lactobacillus is very helpful in helping to break down all the components in breast milk," Dr. Madan explained. "When babies are delivered by C-section, they don't receive those microbes."

Dr. Madan and Dr. Hoen told us they have reason to believe that breast milk and mode of delivery have fairly equal magnitude when it comes to determining a baby's gut health. "That seems to be the case in our study population. We can't necessarily say those effects are going to be equal in another study population," Dr. Hoen said.

Don't think all is lost if you had a C-section or are unable to breastfeed, though. Dr. Madan and Dr. Hoen plan to further study this topic—and moms who have given birth by C-section can likely improve their infant's gut health by feeding him breast milk.

"I would say yes, breast milk is essential. We call it the gold standard. But really, one of the goals in our research is to find out what breast milk creates, what is the typical normal pattern in an infant who is breastfed. We would use that information to investigate interventions—is there we can do if the mom is unable to breastfeed? It would probably be a network of microbiomes that we would introduce to babies as microbiomes," Dr. Hoen said. "There are also some studies going on in New York right now looking at transferring a mom's vaginal microbiome to babies who are delivered by caesarian section. That's really the goal of our research: What is most health-promoting and how can we recreate that?"