The infant gut microbiome is characterized as low in diversity that’s dominated primarily by bifidobacteria and unique to the individual. During approximately the first three years of life, the gut microbiome develops and is largely shaped by various factors including delivery mode (vaginal vs Cesarean birth), maternal antibiotic use, home environment and breastfeeding vs formula feeding. The gut microbiome is later influenced by diet and how long the child was breastfed which affects the gut microbiota composition later in early childhood.

Several recent studies have shed light on the benefits breastmilk have on infant health and their developing gut microbiomes because it contains various components, such as beneficial bacteria, prebiotics called human milk oligosaccharides as well as immune cells, that confer long-term benefits for babies’ health including preventing malnutrition. Additionally, breastfed babies have been found to have less instances of allergies and metabolic disease, yet it is unknown how breastfeeding practices (i.e. nursing vs. pumping) affects the breastmilk composition and infant gut microbiome.

Pumping breastmilk has become a popular and convenient way for mothers to continue to feed their babies breastmilk, yet it is unknown as to whether this method affects the transfer of other non-milk-derived bacteria from the pump or bottles compared to maternal skin for example.