Polat IH, Marin S, Ríos J, et al. - Using exploratory and confirmatory analysis, researchers aimed at determining the presence of vaginal metabolome expression of microbial invasion of the amniotic cavity in women diagnosed with preterm labor using high-performance liquid chromatography. Vaginal amino acid concentrations were assessed using high-performance liquid chromatography among a total of 140 women with singleton pregnancies and a diagnosis of preterm labor below 34 weeks of gestation. Microbial invasion of the amniotic cavity was noted in 17/76 (22.3%) women in exploratory cohort (2014-2015) vs 14/72 (19.4%) in the confirmatory cohort (2016-2017). Significantly higher amino acid concentrations of vaginal taurine, lysine and cysteine and significantly lower concentrations of vaginal glutamate, aspartate and the aspartate/asparagine ratio were observed in the exploratory cohort. The confirmatory cohort confirmed these significant differences. Women with preterm labor and intact membranes exhibit vaginal metabolome expression of microbial invasion of the amniotic cavity. Findings here suggest the possibility for developing non-invasive diagnostic tools of microbial invasion of the amniotic cavity with the aim of selecting women who would most likely benefit from an amniocentesis for this indication.