Human cleavage-stage embryo vitrification is comparable to slow-rate cryopreservation in cycles of assisted reproduction.
OBJECTIVE
To compare embryo survival, pregnancy and implantation rates after cryopreservation of human cleavage-stage embryos with slow-rate cryopreservation or vitrification.


METHODS
262 patients, attending for assisted reproduction, were prepared for oocyte retrieval using standard controlled ovarian hyperstimulation protocols. Excess embryos were cryopreserved on day 3 either by vitrification, or slow-rate cryopreservation in a programmable freezer. Cycles of thawing were monitored for thaw efficiency, pregnancy and implantation rates.


RESULTS
Clinical pregnancy and implantation rates were highly comparable between cycles in which day 3 embryos were thawed either after slow-rate cryopreservation or vitrification.


CONCLUSIONS
These data suggest that vitrification of human embryos during assisted reproduction cycles achieves comparable success rates to fresh cycles and therefore can be applied in the laboratory of assisted reproduction.
Wilding
Martin Graham
MG
Centro Fecondazione Assistita, Clinica Villa del Sole, Napoli, Italy. martinwilding@hotmail.com
Capobianco
Clemente
C
Montanaro
Nadia
N
Kabili
Genc
G
Di Matteo
Loredana
L
Fusco
Enrico
E
Dale
Brian
B
D002970:Cleavage Stage, Ovum; D015925:Cryopreservation / Q000379:methods*; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D011446:Prospective Studies; D027724:Reproductive Techniques, Assisted; D058989:Vitrification