Breastmilk contains many prebiotics to support the growth of beneficial bacteria in the infant’s gut.  It also contains bacteria that seed the infant’s gut.  Previous research has shown that the bacteria in breast milk do indeed take hold and colonize the gut, and so it is imperative to infant microbiome development.  An article published last week sought to discover if the breastmilk microbiome changes depending on mode of delivery, especially since we have seen that C-section infant’s have much different microbiomes than their vaginally delivered counterparts.  The scientists published their results in the journal Microbiome.

The scientists tested the breastmilk of 39 Canadian women.  Despite various backgrounds, each woman’s milk was dominated by Staphylococcus, Enterobacteriaceae, and Pseudomonas.  Moreover, there were not major differences in the breast milk microbiomes between modes of delivery, showing that it is not effected by C-section of vaginal birth.  In addition, the gender of the baby did not change the microbiome either.  Interestingly, the microbiomes were very different between mothers, meaning that babies are being exposed to highly diverse bacteria from milk.  In one case 80% of the bacteria were staphylococci, and in another case more than 50% was Pseudomonas.

There is little evidence that shows how differences in breast milk microbiomes are affecting children.  That said, we know the microbiome is critical to immune system development, and therefore it reasons that these differences may be important.  In any event, it is useful to see that mode of delivery itself is unlikely to change the breastmilk microbiome.