**1. Introduction**

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Egg quality at retrieval in IVF cycles is one of the prime prognostic factors of a successful outcome in IVF cycles. Thus egg donors provide a unique opportunity for assessing the feasibility of new protocols and techniques. In these situations, where the primary reason for resorting to IVF is peri/post menopausal state of the woman, using egg donors assures that at least the quality of the eggs are optimum, and most often the sperm quality, embryo quality at transfer, the recipient's uterus and endometrial condition are not adversely affected.

In patients undergoing *in vitro* fertilization (IVF) procedures one major set of hurdles, which often prevents healthy embryos from resulting in pregnancies, are problems associated with endometrial receptivity and implantation (1-4). From a clinical practice perspective in our new age of pre-implantation diagnosis and screening, the embryo transfer process may now be regarded as a rate limiting factor. Various techniques for embryo transfer (ET) have been advocated to increase pregnancy rates while reducing side effects from the procedure, such as lost embryos and ectopic pregnancies (5-7, 48). In addition, the advantages of using different catheters have been debated (8-11). These methods, however, use a "blind" technique of catheter introduction into the uterus. Since the embryo(s), having the zona pellucida at time of transfer, floats in the uterine cavity between one to three days from the time of transfer, the problems of "lost embryos" and the occurrence of ectopic pregnancies persist. We have hypothesized that the mechanical insertion of the blastocyst into the endometrium under direct visualization would increase the implantation and clinical pregnancy rate of IVF. The aim of this study was to re-investigate the potential of subendothelial ET, a procedure which originated from early mouse experiments (10) and in humans in the mid to late 1990's (12, 13) via trans-abdominal approaches. In contrast to these earlier investigations we propose to use hysteroscopy as a less invasive, visually confirmed, precise and reliable technique to direct and effect the implantation procedure.

© 2012 Kamrava and Yin, licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2012 Kamrava and Yin, licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
