A comparison between two methods of chronological dating of human endometrial biopsies during the luteal phase, and their correlation with histologic dating.

This prospective study was performed on 61 infertile women to examine the correlation between histologic dating using the same criteria by two independent observers and chronological dating by two different methods: (1) determination of luteinizing hormone (LH) peak by daily LH assay, (2) calculation based on the onset of the next menstrual period (NMP). The correlation between histologic dating and chronological dating was found to be significantly better if the LH peak was used to determine the chronological date than if the NMP was used (r = 0.70 and 0.37, respectively).