I-4: Is It Time Now to Cancel Fresh EmbryoTransfer

The implantation of embryo depends on the quality of the embryo and the receptivity of the endometrium. While the factors affecting embryo quality were optimized, the implantation rates did not reach the desirable levels. This directs the blaming for endometrial receptivity which already has been affected by supra-physiological levels of hormone, namely estradiol, in controlled ovarian hyperstimulation (COH) cycle. On the other hand, cryopreservation, especially the vitrification method, has been highly improved to give almost the same results of fresh state, in addition to decreased rate of blastogenesis birth defects. All these encourage us to put our opinion to overcome the problem of endometrial receptivity by cancellation the fresh embryo transfer (fresh ET) and to perform the frozen-thawed embryo transfer (FET) in cases of excessive response to COH.