Comparison of concomitant outcome achieved with fresh and cryopreserved donor oocytes vitrified by the Cryotop method

Objective To evaluate the outcome of oocyte vitrification using the Cryotop method, observed in an egg donation program by simultaneously evaluating embryos derived from vitrified and fresh oocytes coming from the same stimulated cycle. Design Cohort prospective randomized study. Setting Instituto Valenciano de Infertilidad (IVI) Valencia, Spain. Patient(s) Thirty oocyte donors and 30 recipients with informed consents. Intervention(s) Vitrification by the Cryotop method. Warming 1 hour after vitrification. Microinjection of surviving MII and fresh oocytes, evaluation of fertilization, embryo development, and clinical results. Main Outcome Measure(s) Survival, fertilization, and cleavage rat…