Integrative analysis of oral microbiota and its gut transmission with host immunity in term pregnancy

This study aims to evaluate associations between the oral microbiota, metabolites, potential oral-gut transmitted microbes, and systemic immune alterations in term pregnancy. Oral and gut microbiomes, salivary metabolome, peripheral immune cells, and cytokines were profiled in term pregnant (n = 25) and non-pregnant women (n = 25). Species enriched in pregnancy, including Streptococcus anginosus and Prevotella denticola, correlated positively with the NK cell ratio, while Prevotella histicola and Prevotella micans correlated positively with CD56brightCD16− NK cells. Mediation analysis indicated that fatty acids in saliva may not mediate the impact of oral microbiota on peripheral immune changes during pregnancy. Several potential oral–gut transmitted microbes with a higher maternal transfer ratio were positively associated with CD56brightCD16− NK cells and the NK cell ratio, but negatively with Th1 cells and the Th1/Th2 ratio. These findings provide preliminary evidence that pregnancy-related immune shifts may be linked to oral microbiota alterations and microbial transmission.