[Study of plasma metabolic markers in unexplained recurrent spontaneous abortion based on non-target metabolomics approach].

<b>Objective:</b> To screen plasma metabolic markers in patients with unexplained recurrent spontaneous abortion (URSA) by non-target metabolomics approach. <b>Methods:</b> From September 2022 to May 2023, the plasma of 23 URSA pregnant women with threatened abortion who visited the outpatient clinic of Gansu Provincial Maternity and Child-care Hospital in the first trimester (URSA group) was collected, and the plasma of 22 healthy pregnant women in the first trimester who underwent prenatal examination during the same period (normal control group) was collected. Plasma metabolomics was analyzed by ultra performance liquid chromatography (UPLC) coupled with mass spectrometry (MS), fold change analysis, principal component analysis and partial least square discriminant analysis were applied to screen for differential metabolites, and the metabolites and their pathways associated with URSA were screened using receiver operating characteristic (ROC) curve and pathway enrichment analysis. <b>Results:</b> There were no significant differences in age, body mass index and gestational weeks between URSA and normal control group(all <i>P</i><0.05). Metabolomics analysis using UPLC-MS showed that a total of 526 metabolites were detected from plasma, of which 33 were found to be differential metabolites associated with URSA based on the screening standards. Six potential metabolites with large area under the curve (AUC) were identified by ROC curve analysis, including phosphatidylethanolamine (AUC=0.972, 95%<i>CI</i>: 0.920-1.000), santene hydrate (AUC=0.902, 95%<i>CI</i>: 0.786-0.982), L-leucine (AUC=0.884, 95%<i>CI</i>: 0.772-0.960), cembrene (AUC=0.881, 95%<i>CI</i>: 0.758-0.956), caffeine (AUC=0.875, 95%<i>CI</i>: 0.756-0.962), and 4-hydroxybenzoic acid propyl ester (AUC=0.864, 95%<i>CI</i>: 0.732-0.946). The AUC for the combined diagnosis of URSA by the six metabolites was 0.983 (95%<i>CI</i>: 0.929-1.000). Pathway enrichment analysis of the differential metabolites showed that the pathogenesis of URSA was associated with a variety of metabolic pathways including caffeine metabolism, glycerophospholipid metabolism, and unsaturated fatty acid biosynthesis. <b>Conclusion:</b> The plasma metabolic profiles of pregnant women with normal pregnancies versus URSA differ in early pregnancy, and six potential metabolites such as phosphatidylethanolamine, santene hydrate, L-leucine, cembrene, caffeine, 4-hydroxybenzoic acid propyl ester, and their metabolic pathways may be involved in the pathogenesis of URSA.