Microbial dysbiosis and immunological dysregulation in pathological pregnancy.

Adverse perinatal outcomes of preterm birth (PB), premature rupture of membranes (PROM), intrauterine growth restriction (IUGR), and preeclampsia contribute to a growing number of maternal and fetal deaths each year. Altered immunological regulation of the maternal innate and adaptive immune systems has been implicated in the pathological inflammation dictating obstetrical complications, but the pathogenesis of aberrant maternal immune activation has not been fully elucidated. Microbial dysbiosis within the female reproductive tract may alter the regulation of immunological tolerance at the maternal-fetal interface, mediating maternal inflammation that precipitates obstetrical disorders. Development of a more comprehensive understanding on how microbial communities influence immune regulation during pregnancy may create avenues for therapeutic modulation of the maternal immune system to promote immune tolerance throughout gestation and decrease obstetrical complications. In this review we characterize the modulation of maternal immunological function by microbial communities and how these pathways may precipitate the development of obstetrical disorders.