Microbiome in parturition and preterm birth.

Preterm parturition is a one of the most significant global maternal-child health problem. In recent years, there has been an explosion in reports on a role for microbiomes (i.e., a microbial biomass) on a plethora of physiologic and pathologic human conditions. This review aims to describe our current understanding of the microbiome and its impact on parturition, with particular emphasis on preterm birth. We will focus on the roles of vaginal and oral mucosal microbiomes in premature parturition and describe the state-of-the-art methodologies used in microbiome studies. Next, we will present new studies on a potential microbiome in the placenta and how it may affect pregnancy outcomes. Finally, we will propose that host genetic factors can perturb the normal "pregnancy microbiome" and trigger adverse pregnancy outcomes.