Interactions of the maternal microbiome with diet, stress, and infection influence fetal development.

Humans and other animals contain multitudes of microorganisms including bacteria, fungi, and viruses, which make up a diverse microbiome. Across body sites including skin, gastrointestinal tract, and oral cavity there are distinct microbial niches that are made up of trillions of microorganisms that have co-evolved to inhabit and interact with the host. The microbiome also interacts with the changing environment. This tripartite interaction between the host, microbiome, and environment suggests microbial communities play a key role in the biological processes of the host, such as development and behaviors. Over the past two decades, emerging research continues to reveal how host and microbe interactions impact nervous system signaling and behaviors, and influence neurodevelopmental, neurological, and neurodegenerative disorders. In this review, we will describe the unique features of the maternal microbiome that exist during the perinatal period and discuss evidence for the function of the maternal microbiome in offspring development. Finally, we will discuss how the maternal environment interacts with the microbiome and nervous system development and then postulate how the maternal microbiome can modify early offspring development to have lasting influence on brain health.