Deferred Embryo Transfer in an In Vitro Program With Single Embryo Transfer Policy

Single embryo transfer decreases the multiple pregnancy rate and its complications. However, studies are needed to help increase the effectiveness of this technique to increase its use, which undoubtedly improves the safety of our patients. Objectives: To assess the results of IVF / ICSI cycles with single embryo transfer, in terms of both pregnancy and live birth rates, comparing a group of patients in which an elective delayed cryotransfer of an embryo without fresh transfer is performed (experimental group ), with patients in whom a fresh embryo is transferred electively. Methodology: A prospective randomized clinical trial with two arms in parallel, not blinded, including 138 couples using an IVF / ICSI cycle at the Reproduction Unit of the Hospital Universitario Virgen de las Nieves de Granada. The inclusion criteria classify them as having a good reproductive prognosis, and the patients will follow an ovulation treatment protocol with GnRH agonists or antagonists. Couples will undergo an IVF / ICSI cycle, randomly assigned to: * Group I (experimental): fresh transfer is not performed, the best quality embryo is cryopreserved. Elective transfer in a later cycle of the cryopreserved embryo. * Group II (control): fresh transfer of the best quality embryo.