Successful implantation depends on synchronization between a normal functional embryo at the blastocyst developmental stage and a receptive endometrium. The endometrium is receptive to blastocysts during a spatially and temporally restricted time window called the window of implantation. Failure of the endometrium to attain receptivity is one cause of infertility, and this is not currently assessed during infertility workup due to a lack of reliable markers for receptivity. Better tests are required to assist the clinician with the decision when to defer a transfer and to freeze all embryos. Proteomics, or the analysis of the proteins in any sample, provides physiologically relevant information, since there are many regulatory steps between the transcriptome and functional proteins. Uterine fluid is a protein-rich histotroph that contains, among other components, secretions from the endometrial glands and cleavage products of both the secreted proteins and the glycocalyx. The aim of this study is to assess the highly sensitive mass spectrometer analysis of the proteins from cervical mucus for the detection of defects in endometrial receptivity and search for new endometrial receptivity biomarkers.
Analysis of proteins from cervical mucus will be done in patients undergoing infertility treatment (fresh or frozen embryo transfer). Cervical mucus will be analysed for potential new biomarkers of endometrium receptivity. Comparison of the peptide spectrum will be done for the pregnant and not pregnant patients.