Recovery and maturation of immature oocytes in patients at risk for ovarian hyperstimulation syndrome

Purpose: Our purpose was to examine the rate of immature oocyte recovery and their potential for in vitro maturation from canceled human menopausal gonadotropin cycles due to the risk of having ovarian hyperstimulation syndrome develop. Methods: Patients underwent ultrasound-guided immature oocyte pickup. The number of oocytes recovered from these patients was recorded, and then cultured in vitro. Cumulus expansion and the stage of nuclear maturation were observed after 24 and 48 hr, respectively. Results: Seventeen patients underwent 20 immature oocyte recoveries. A total of 162 oocytes (8.1 oocytes/patient) was obtained. All of the oocytes were enclosed in dense layers of cumulus cells. Among them, 78.4% showed cumulus expansion after 24 hr and 66% completed meiotic maturation to metaphase II after 48 hr in culture. There was only one immature oocyte pickup in which no oocytes were recovered (95% recovery rate). None of the patients had ovarian hyperstimulation syndrome develop. Conclusions: Immature oocytes carl be recovered from canceled human menopausal gonadotropin cycles in patients who are at potential risk for severe hyperstimulation syndrome. These oocytes can be matured in vitro and can be used for clinical and research purposes as well.