Cryopreservation of Embryos and Oocytes in Human Assisted Reproduction

Abstract

Both sperm and embryo cryopreservation have become routine procedures in human assisted reproduction and oocyte cryopreservation is being introduced into clinical practice and is getting more and more widely used. Embryo cryopreservation has decreased the number of fresh embryo transfers and maximized the effectiveness of the IVF cycle. The data shows that women who had transfers of fresh and frozen embryos obtained 8% additional births by using their cryopreserved embryos. Oocyte cryopreservation offers more advantages compared to embryo freezing, such as fertility preservation in women at risk of losing fertility due to oncological treatment or chronic disease, egg donation, and postponing childbirth, and eliminates religious and/or other ethical, legal, and moral concerns of embryo freezing. In this review, the basic principles, methodology, and practical experiences as well as safety and other aspects concerning slow cooling and ultrarapid cooling (vitrification) of human embryos and oocytes are summarized.

Chromosomal meiotic segregation, embryonic developmental kinetics and DNA (hydroxy)methylation analysis consolidate the safety of human oocyte vitrification

“…The information available on the neonatal outcome and the long-term follow-up of children conceived after oocyte cryopreservation is limited (Chian et al, 2008(Chian et al, , 2014Noyes et al, 2009;Wennerholm et al, 2009;Cobo et al, 2014) and only small studies have specifically addressed the safety of oocyte vitrification (Coticchio et al, 2009;Bonetti et al, 2011;Chen et al, 2012;Forman et al, 2012;Khalili et al, 2012;Monzo et al, 2012;Dominguez et al, 2013;Gugliemo et al, 2014;Konc et al, 2014;Nohales Có rcoles et al, 2014;Palmerini et al, 2014).…”

Glycine increases preimplantation development of mouse oocytes following vitrification at the germinal vesicle stage

“…Cryopreservation of oocytes, is standard practice in Assisted Reproductive Technologies123 (ART). Indeed, the experimental connotation, once associated with oocyte cryopreservation has been removed45.…”

Live birth after transfer of vitrified-warmed embryo derived from vitrified-warmed oocyte and frozen-thawed sperm following failed ICSI: Case report

“…It would permit the storage of reproductive potential for women at risk of loss of fertility when undergoing cytotoxic therapy, allow storage of oocytes when sperm retrieval is not possible in a cycle of IVF treatment. Oocyte cryopreservation offers more advantages compared to embryo freezing, such as fertility preservation in women at risk of losing fertility due to oncological treatment or chronic disease, egg donation, and postponing childbirth, and eliminates religious and/or other ethical, legal, and moral concerns of embryo freezing 5 . Numerous individual studies investigating the different reproductive outcomes of cryopreservation on human embryos, immature or mature oocytes, or ovarian tissues have been reported.…”