LAUSR

For the present study we asked whether the endometrial fluid lipidomic may be a useful approach to predict endometrial receptivity in freeze‐all cycles. For this case‐control study, endometrial fluid samples were collected from 41 patients undergoing freeze‐all cycles. Samples were split depending on the pregnancy outcome: positive group (n = 24) and negative group (n = 17). Data were acquired by the matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS‐DA) were applied. A list of potential biomarker ion ratios was obtained and the values were used to build a receiver operating characteristic (ROC) curve to predict pregnancy success. The lipid categories were attributed by LIPID MAPS database. Ion ratios were established according to their correlations and used for the analysis. The PCA showed a tendency of separation between the studied groups, whereas the PLS‐DA was able to clearly distinguish them. Fifteen ratios (13 hyper‐represented in the negative and two hyper‐represented in the positive group) were selected according to their importance for model prediction. These ratios were used to build the ROC curve, which presented an area under curve of 84.0% (95%CI: 69.2–97.4%; p = 0.009). These findings suggest that lipidomic profiling of endometrial fluid may be a valuable tool for identifying the time interval comprising the window of implantation.