Delivery after transfer of frozen-thawed embryos from in vitro-matured oocytes in a woman at risk for ovarian hyperstimulation syndrome

The present report describes the birth of a healthy infant after cryopreservation of embryos produced from in vitro-matured oocytes retrieved from a woman at risk of developing ovarian hyperstimulation syndrome (OHSS) during conventional in vitro fertilization (IVF) cycles. A conventional long protocol including gonadotropin-releasing hormone agonist (GnRHa) and gonadotropins induced a risk of OHSS. Oocyte retrieval was performed on day 11 of the cycle, and 27 immature oocytes were obtained. Following incubation for 24 h in maturation medium, 74.1% (20/27) of the oocytes were at the metaphase II stage. Fourteen oocytes (14/20, 70.0%) were fertilized after intracytoplasmic sperm injection (ICSI) with her husband's spermatozoa and cultured for 3 days. On day 4 following oocyte retrieval, three embryos at the 8-16 cell stage were transferred into the woman's uterus, and five spare embryos were frozen. Since the fresh embryo transfer failed to result in pregnancy, three post-thaw embryos were transferred into the woman three months later. Transfer of the frozen embryos resulted in pregnancy with delivery of a healthy infant girl.