ABSTRACT
The human body has trillions of microbes inhabiting every surface exposed to the environment, both inside and out, termed the microbiome. Improvements in high-throughput methodologies, coupled to reducing costs, have profoundly improved the ability to survey the microbiome. Under normal circumstances neonates are generally thought to be sterile in the intrauterine environment, with the first exposure to microbes occurring during birth. However, intriguing emerging evidence also suggests that bacterial DNA might be present in the placenta. There are many factors that influence the maternal microbiome at various body sites, which in turn influence the neonatal microbiome. Vaginally delivered neonates are initially colonized by bacterial communities that resemble the vaginal microbiome, resulting in dominant bacteria genera. The gestational age refers to the number of weeks from the last menstrual cycle of the mother to the birth of the infant. The initial seeding of the microbiome in the prenatal stages and through birth represents an important period of the newborn infant.
