Where Does the Baby's Microbiome Come From?
It was identified that maternal microbes contribute to a baby's gut colonisation through the colostrum (1).
Breast Milk for Establishment of the Baby's Gut Microbiome.
After birth, breast milk modulates the infant gut microbiota by providing factors that selectively promote the growth of specific microbes, such as bifidobacteria (2). Furthermore, there are data that suggest microbes exist in breast milk and that they are the repeating colonising inoculum to the neonatal gut (3, 4).
Probiotics Are safe.
Probiotics do not appear to pose any safety concerns for pregnant and lactating women in recent studies (5).