Insights into the alteration of vaginal microbiota and metabolites in pregnant woman with preterm delivery

Preterm delivery is a major reason of perinatal morbidity and mortality. The disorder of vaginal microbiota and metabolites in pregnant women may be the most important risk factor for preterm delivery. This study aims to explore whether vaginal microbiota and metabolites alteration may elevate the risk of preterm delivery. In this study, 63 cases of pregnant women were enrolled, comprising 32 cases of women with term births and 31 cases of women with preterm births. Compared with the pre-cerclage in the term birth group (PrTG), the proportion of beneficial bacteria ( Lactobacillus , Prevotella , Trichococcus , Neisseria and Gemella ) in the pre-cerclage in the preterm birth group (PrPG) were significantly reduced ( p  < 0.05), while the proportion of harmful bacteria ( Thauera , Ochrobactrum , Gardnerella , Massilia , Phyllobacteriaceae and Atopobium ) were significantly increased ( p  < 0.05), which is strongly associated with the preterm birth. In addition, vaginal metabolomics-based LC-Orbitrap-MS/MS revealed that the contents of 2-Piperidone, Melphalan, N-acetylputrescine, Obatoclax, Eurostoside, Pregnanediol 3-O-glucuronide, O-Phospho-L-serine, 1-Kestose and N-arachidonylglycine were significantly decreased in the PrPG group compared with the PrTG group, while Acenocoumarol, Isopyrazam, Pentosidine, hexose, 7-Hydroxymitragynine, PE, Tamoxifen and 1-Deoxynojirimycin contents were significantly increased. These results elaborate that several candidate bacteria and metabolites could be applied as the prospective predictors for preterm birth, and approve the theoretical basis for the internation of preterm birth.