FIGURE 1.

The study design of metabolic profiling of serum samples from women with PROM in the first trimester. There were three steps: 1) 408 pregnant women were enrolled, and 379 serum samples were collected in the first trimester. Of these women, 196 were excluded for miscarriage or induced labor (n = 12), missing clinical outcome data (n = 67), diagnosis of another disease (n = 107) or PROM complicated with other definite diseases (n = 46). Finally, 41 samples from women with PROM and 106 from healthy controls were included. 2) Metabolomics data processing using untargeted metabolomics was based on HPLC–HRMS, and the peaks were extracted and normalized; the features were identified according to compound databases. 3) The statistical analysis included identification of PROM-related differential metabolites and changes in metabolite groups in PROM in the first trimester; the final combined model included four potential biomarkers for predicting PROM.