Birth after cryopreservation of immature oocytes with subsequent in vitro maturation

Objective: To establish the clinical feasibility of using cryostored germinal vesicle oocytes for IVF and ET. Design: Case report. Setting: Private infertility clinic. Patient(s): A 28-year-old woman with tubal infertility undergoing IVF therapy. Intervention(s): Oocytes collected after ovarian stimulation were frozen without insemination or were inseminated, fertilized, and frozen as cleavage stage embryos. No fresh oocyte or embryo transfer was undertaken. All oocytes were thawed, and those that survived were used for IVF-ET. Main Outcome Measure(s): Oocyte cryosurvival, in vitro maturation, fertilization, embryo development, and pregnancy outcome. Result(s): None of 16 mature oocytes survived thawing; however, three of 13 germinal vesicle oocytes survived. After 30 hours in vitro maturation two oocytes had matured and underwent intracytoplasmic sperm injection with the partner's sperm. Both fertilized normally and were transferred to the patient. The woman delivered an apparently healthy female infant at 40 weeks. Conclusion(s): This case report proves the feasibility if not the efficiency of using immature oocytes for cryostorage, coupling both cryopreservation and in vitro maturation. (Fertil Steril(R) 1998;70:578-9. (C) 1998 by American Society for Reproductive Medicine.).