Clinical application of human egg cryopreservation.
Clinical egg cryopreservation has been applied during a 4-year period with some limited success. Mostly mature and a few immature eggs were frozen slowly and thawed rapidly in 1,2-propanediol and sucrose, and subsequently inseminated by intracytoplasmic sperm injection (ICSI). Three studies were performed in which: (i) it was established that 55% of aged unfertilized mature eggs survive freezing; (ii) in 22 cycles of thawed donated eggs cryosurvival was 24% with 15 cycles reaching transfer, and five pregnancies were initiated, one of which went to term at 39 weeks with fraternal twin boys, and one remains ongoing at 37 weeks; and (iii) in five cycles, where in-vitro fertilization patients had some of their own eggs frozen/ thawed, cryosurvival of mature eggs was poor at only 2.2%, although 44% sibling germinal vesicle (GV) stage eggs survived. A normal female infant delivered at 40 weeks arose from transfer of two embryos where GV eggs underwent in-vitro maturation post-thaw and were fertilized by ICSI. Pregnancies reported here and by others indicate a burgeoning awareness of the potential benefits of egg cryopreservation, prompting cautious optimism for the future of this technology.
Tucker
M J
MJ
Reproductive Biology Associates, Atlanta, Georgia 30342, USA.
Morton
P C
PC
Wright
G
G
Sweitzer
C L
CL
Massey
J B
JB
D000328:Adult; D015925:Cryopreservation; D003451:Cryoprotective Agents; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods; D006801:Humans; D008297:Male; D008845:Microinjections; D018587:Oocyte Donation; D009865:Oocytes / Q000502:physiology*; D011247:Pregnancy; D011256:Pregnancy Outcome; D019946:Propylene Glycol; D013395:Sucrose; D013997:Time Factors; D014427:Twins
D003451:Cryoprotective Agents; D013395:Sucrose; D019946:Propylene Glycol