We are currently investigating the role that resident microbes play in shaping the fetal microbiome during the latter half of gestation using a naive ovine model (no antibiotic treatment or indwelling devices). This study not only assesses the fetal brain but all other organ systems. Our data strongly suggests that bacteria are vertically transmitted from mom to fetus in utero and that these bacteria form unique niches within the intrauterine compartment. In healthy pregnancies, these bacteria may stimulate fetal immune development prior to birth and give rise to an early gut microbiome.