title: Cryopreservation of human embryos and oocytes.
abstract: Human embryo cryopreservation is now a fully established adjunct to assisted reproduction, with thawed embryos implanting at a rate approaching that of fresh embryos. As with fresh embryos, the quality of frozen-thawed embryos is affected by patient age at the time of oocyte retrieval, and by culture conditions. Ovarian stimulation incorporating gonadotropin-releasing hormone analogs does not appear to be detrimental to cryopreservation success, and natural or artificial thaw cycles seem equally effective. Successful cryopreservation seems feasible for one- to eight-cell embryos and blastocysts using a variety of protocols. Selection criteria for embryos to be frozen can vary, and embryo quality has the most significant impact on post-cryopreservation viability. Unfertilized oocyte cryopreservation is coming closer to routine clinical application.
authors.affiliation: Reproductive Biology Associates, Atlanta, Georgia, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Tucker
authors.forename: P C
authors.initials: PC
authors.lastname: Morton
authors.forename: C L
authors.initials: CL
authors.lastname: Sweitzer
authors.forename: G
authors.initials: G
authors.lastname: Wright
mesh_terms: D015925:Cryopreservation / Q000379:methods*; D004624:Embryo Transfer; D004622:Embryo, Mammalian; D005260:Female; D006801:Humans; D009865:Oocytes; D011247:Pregnancy