Determining the most optimal stage for embryo cryopreservation.
The objective of this study was to compare cleaved embryo and blastocyst freezing to determine the optimal time for embryo cryopreservation. A retrospective analysis was carried out for all frozen embryo transfer cycles where transfer occurred on either day 3 or day 5. Blastocyst freezing increased the ongoing pregnancy, implantation and survival rates post-thaw as compared with cleaved embryo thaws. There was no difference in ongoing pregnancies for fresh and frozen-thawed blastocyst transfers (59% versus 62%) respectively. Additionally, fresh blastocyst transfers had a higher proportion of supernumerary embryos cryopreserved than did day 3 transfers (38% versus 26%). Blastocyst freezing is a viable option for handling patient's supernumerary embryos while optimizing pregnancy outcomes per oocyte retrieval.
Presbyterian Hospital Institute for Assisted Reproduction, 200 Hawthorne Lane, 6A-IVF, Charlotte, North Carolina, 28204, USA. Tranderson@novanthealth.org
Anthony R
AR
Anderson
Margaret L
ML
Weikert
Jack L
JL
Crain
D001755:Blastocyst / Q000502:physiology*; D002970:Cleavage Stage, Ovum / Q000502:physiology*; D015925:Cryopreservation; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D011247:Pregnancy; D013997:Time Factors