Implantation failure remains a significant problem in cycles of in vitro fertilization (IVF). Patients with a history of implantation failure in fresh autologous cycles have been shown have reduced chance of success in subsequent fresh autologous cycles. A potentially frequent cause of implantation failure is reduced endometrial receptivity following ovarian stimulation, perhaps due to the effects of supraphysiologic hormone levels on endometrial development. Therefore, such patients may have a greater chance of success if all of their embryos are cryopreserved for use in a subsequent cycle in which endometrial development can be more carefully controlled, absent the effects of ovarian stimulation. Therefore this study compares success rates in cycles of fresh embryo transfer and cycles with transfer of frozen-thawed embryos.