The impact of endometrial preparation on implantation following cryopreserved-thawed-embryo transfer.

The efficacy of three protocols of endometrial preparation (spontaneous cycles, A: artificial preparation, B; ovarian stimulation, C) for cryopreserved-thawed human embryo transfer (CT-ET). The implantation and clinical pregnancy rates per cycle in 236 women undergoing 381 consecutive CT-ETs were evaluated according to the endometrial preparation protocol. No statistically significant difference was found in implantation rates per embryo transfer (A = 5.6%, B = 5.6%, C = 4.6%) and clinical pregnancy rates per cycle (A = 16.9%, B = 16.5%, C = 15.6%) between the three endometrial preparation protocols used. In conclusion, the specific method of endometrial preparation for CT-ET had no significant impact upon the implantation rate.