Establishment of the early gut microbiota in vaginally delivered infants: the influence of maternal gut microbiota outweighs vaginal microbiota

Gut microbiota exerts a significant impact on an individual's long-term health; however, its origins and colonization processes remain to be fully elucidated. This study revealed that early infant gut microbiota of vaginally delivered infants primarily derived from maternal gut microbiota, which began colonizing the fetus as early as 32 weeks of gestation. In contrast, the contribution of maternal vaginal microbiota to early infant gut microbiota was quite limited. Moreover, placental microbiota also constituted an important source for the fetal gut microbiota. These findings provide novel insights into the developmental mechanisms of infant gut microbiota and highlight the important role of maternal microbes in the early colonization of infant gut microbiota.