Objective : to explore the benefits of the E2 priming during the luteal phase in women with poor ovarian response (POR) undergoing IVF cycles using the GnRH antagonist protocol.   
Methods : This randomized controlled study conducted on 100 POR underwent ICSI trial using GnRH antagonist protocol assigned to 1 group of 2. Group I included 50 women received oral E2 valerate 4 mg/day started on luteal day 21 and continued up to the 1st day of the cycle group II included 50 control women who did not receive estrogen priming. The main outcome parameter was the number of MII oocytes. Other outcomes included implantation, chemical pregnancy and clinical pregnancy rates.   
Results: No statistically significant difference between women in the estrogen priming group and other women regarding the retrieved oocytes number and quality, implantation, clinical pregnancy, or chemical pregnancy rates.  
Conclusion: estrogen priming did not increase the number of MII retrieved ova in POR.