Assessment of vaginal microbiome-metabolite and host immune interactions associated with spontaneous preterm birth in a predominantly caucasian population

IntroductionPreterm birth is linked to host vaginal immune-microbiome interactions. The microbial induced metabolome and immune response can unveil unique pathways in the pathomechanism of spontaneous preterm birth (sPTB). In this study, we investigated vaginal microbiome-metabolite and host immune interactions associated with sPTB in a predominantly caucasian population of asymptomatic pregnant women across the second trimester. This was in order to better understand the pathomechanism of sPTB and improve risk stratification.MethodsCV fluid was collected from asymptomatic high-risk pregnant women at two gestational time points. Samples were eluted in phosphate buffered saline and the aqueous fraction was analysed by Electrospray Ionization Time-of-Flight Mass Spectrometry. Differences in metabolite normalised % total ion count between the groups were analysed using the Omu metabolomics analysis R package.ResultsA tlist metabolites were identified. Fifty-four metabolites differed between gestation time point one and gestation time point two.ConclusionThese findings indicate the CV microbiome and metabolome is dynamic and changes across the midtrimester of pregnancy, long before any symptoms of preterm labour appear. We also show that women who experience sPTB show increasing concentrations of infection-associated metabolites such as putrescine and pyruvate across the second trimester of pregnancy. Gestational changes in cervicovaginal concentration of these metabolites may suggest increased risk of sPTB and could improve pregnancy risk stratification, subject to confirmatory future clinical studies.