Vitrification is a highly efficient method to cryopreserve human embryos in in vitro fertilization patients at high risk of developing ovarian hyperstimulation syndrome

This study aimed to evaluate the efficacy of embryo vitrification as an emergency procedure for patients at high risk of developing ovarian hyperstimulation syndrome (OHSS). A total of 69 embryos, derived from 24 patients for whom embryo transfer could not be performed because of the risk of developing OHSS, were vitrified and warmed for deferred embryo transfer. Surviving embryos were transferred, resulting in 10 clinical pregnancies, of which 4 were successfully delivered and the remaining 6 are still ongoing. (Fertil Steril (R) 2009;91:1611-3. (C) 2009 by American Society for Reproductive Medicine.)