Cryopreservation of Human Embryos

Yoon, Tae Ki; Chung, Hyung Min; Lim, Jeong Mook; Cha, Kwang Yul

Abstract

Technology for the long-term preservation of gamete and embryo has improved greatly over the past 20 years and currently is used for supporting various assisted reproductive technologies (ART). Recent progress in cryobiology and its related sciences have made it possible to preserve human embryos effectively, and several cryopreservation methods also have been developed. Successful freezing of supernumerary embryos has allowed patients undergoing ART the opportunity to achieve pregnancies from more than one embryo transfer without being subjected to controlled ovarian hyperstimulation and oocyte retrieval each time. It also allows a delay in embryo transfer where certain adverse conditions exist for fresh transfer, e.g. when the patient is at risk for ovarian hyperstimulation syndrome or when there is poor endometrial development during the retrieval cycle. Cryopreservation of all available embryos from retrieval is utilized when an oocyte recipient is not properly synchronized with oocyte donor's cycle. In this paper is to review the current status and perspectives of embryo cryopreservation in ART program. Also, briefly discuss the oocyte cryopreservation for the establishment of ovum bank.