Determining the time of the urinary luteinizing hormone surge: Does it facilitate the interpretation of endometrial biopsy results?

Recent data suggest that endometrial maturation correlates highly with the postovulatory day as determined by ultrasound or identification of the urinary luteinizing hormone (LH) surge. A study was performed to determine the level of correlation between two methods of endometrial biopsy (EB) interpretation. Method 1 correlated histology with the onset of the next menstrual period; method 2 correlated it with the postovulatory day relative to the LH surge. Forty EBs were analyzed. Both methods agreed that 20/40 EBs were in phase and 6/40 EBs were out of phase (greater than a two-day lag between histologic endometrial maturation and chronologic dating). Of the remaining 14 EBs, 8 were in phase by method 1 and out of phase by method 2, and 6 were out of phase by method 1 and in phase by method 2. Thus, 35% of EBs were considered in phase by one method and out of phase by the alternative method. This implies that 35% of management decisions regarding whether to repeat an EB or treat an out-of-phase EB may be influenced by the method of interpreting EBs.