Live birth following transfer of a cryopreserved embryo generated from a cryopreserved oocyte and a cryopreserved sperm: Case report

Abstract

As is the case with non-frozen oocytes, the efficient and successful use of cryopreserved oocytes in human assisted reproduction is, in part, dependent on the ability to apply selection criteria when choosing the 'best' embryos for transfer from a cohort. In many cases this, in turn, will necessitate the cryopreservation of non-transferred embryos to minimise the risk of multiple pregnancy. It is therefore important to establish that an embryo, generated by fertilization of a frozen-thawed oocyte, can be capable of surviving subsequent cryopreservation while retaining the potential for normal development. In this case report, we document the delivery of a normal male infant following transfer of a frozen-thawed embryo, generated by the fertilization of a frozen-thawed oocyte by a frozen-thawed sperm.

Pregnancies and deliveries after injection of vitrified-warmed oocytes with cryopreserved testicular sperm

“…After replacement of all derived viable embryos, four clinical pregnancies were established (pregnancy rate ¼ 36.4%), of which two successfully delivered healthy infants. These results support previously published sporadic case reports of healthy births after microinjection of cryopreserved oocytes, either by slow-freezing or vitrification, with frozen-thawed ejaculated or surgically retrieved epididymal or testicular spermatozoa (21)(22)(23)(24)(25)(26)(27).…”

Implantation rates of embryos generated from slow cooled human oocytes from young women are comparable to those of fresh and frozen embryos from the same age group

“…Four of the 12 implantations resulted from the transfer of frozen/thawed embryos which had been generated from cryopreserved oocytes. We have previously described one of these cases in which implantation and live birth resulted from the transfer of a cryopreserved embryo which had been generated from injection of a cryopreserved sperm into a cryopreserved oocyte [30]. From January 2004 onwards, the implantation rate from over 7000 ICSI generated day 2 embryos in women of the same age in our clinic was 26.0%.…”

Human oocyte cryopreservation

“…Increasing the concentration of the non-permeating sucrose from 0.1-0.2 or 0.3 M during dehydration was reported to increase survival to 60 and 82%, respectively (Fabbri et al, 2001). These modifications have continued to maintain higher survival rates of around 70% when data is pooled from clinical studies using 0.2 M sucrose (Yang et al, 1998(Yang et al, , 2002Porcu et al, 1999;Winslow et al, 2001;Bianchi et al, 2007;Gook et al, 2007) and slightly higher (74%) using 0.3 M sucrose (Chen et al, 2002(Chen et al, ,2005Fosas et al, 2003;Li et al, 2005;Tjer et al, 2005;Borini et al, 2006b;Chamayou et al, 2006;La Sala et al, 2006;Levi Setti et al, 2006;Barritt et al, 2007;De Santis et al, 2007;Konc et al, 2007).…”

“…Although protocols using both 0.2 and 0.3 M sucrose have been applied clinically (Table 2), more extensive experience has been reported for 0.3 M sucrose which has been used for oocytes from over 800 patients in 11 clinics (Chen et al, 2002(Chen et al, , 2005Fosas et al, 2003;Li et al, 2005;Tjer et al, 2005;Chamayou et al, 2006;La Sala et al, 2006;Levi Setti et al, 2006;Borini et al, 2006b;Barritt et al, 2007;De Santis et al, 2007;Konc et al, 2007). Outcomes from oocyte cryopreservation using 0.2 M sucrose have been reported for 200 patients in 6 clinics (Yang et al, 1998(Yang et al, , 2002Porcu et al, 1999;Kyono et al, 2001;Winslow et al, 2001;Montag et al, 2006;Bianchi et al, 2007;Gook et al, 2007). Clinical experience of higher sucrose concentration procedures has substantiated the initial reports of higher survival rates with reported rates using 0.2 M ranging from 68 -76% and using 0.3 M ranging from 69 -90%.…”