A difference exceeding 3 days between histoogical dating and the chronological cycle day on the day of oocyte retrieval in IVF cycles appears to be incompatible with a ongoing clinical pregnancy. Such difference is observed only in a minority of patients (10%) and is thus not applicable as an endometrial receptivity marker in clinical practice.
Dating according to Noyes criteria is referred as the golden standard for clinical diagnosis and management of patients with endometrial pathology. Recent studies challenged the method due to significant inter-and intra-observer variation. Histological dating is not precise for evaluation of short cycle intervals (Murray, 2004) and is unable to discriminate in a natural cycle between women from fertile and infertile couples (Coutifaris, 2004). A very recent study explored endometrial tissue on different cycle days in natural cycles. Samples with known and unknown histology could be classified in a specifical phase of the menstrual cycle according to their molecular gene expression profile. (Talbi, 2005). These results allow for global identification of biological processes and molecular mechanisms that occur dynamically during the menstrual cycle.
In our centre, the availability of endometrial tissue collected in IVF cycles at oocyte retrieval prior to embryo transfer as well as the results of pregnancy outcome in these cycles allow to extent the study by Talbi et al. to endometrial tissue from IVF cycles and to explore clinically applicable markers for endometrial receptivity.
The current project aims to extend the preliminary results on gene expression data in endometrial tissue from cycles with ovarian stimulation, to validate the potential candidate genes with Q-RT-PCR and to conduct a longitudinal study by immunohistochemistry in several stages of the normal and stimulated menstrual cycle. In a prospective setting, the candidate markers will be tested for their predictive value for pregnancy outcome.