The value of fast blastocoele re-expansion in the selection of a viable thawed blastocyst for transfer.
OBJECTIVE
To investigate the role of fast blastocoele re-expansion in the selection of viable thawed blastocysts for transfer.


METHODS
Retrospective study.


METHODS
Academic assisted reproductive program.


METHODS
Transfer cycles were divided into two groups according to the presence or absence of fast re-expanded blastocysts. In group I (124 cycles), all transferred blastocysts had fast re-expanding blastocoele. In group II (113 cycles), no fast re-expanded blastocysts were included in the transfer.


METHODS
Blastocyst survival was defined as >50% of cells remaining intact after thaw and re-expansion after culture in vitro for 2-4 hours before transfer. Blastocysts with >or=50% re-expansion were designated as fast re-expanded blastocysts.


METHODS
Percentage of blastomere loss immediately after thaw, degree of blastocoele re-expansion, and clinical outcomes (pregnancy and implantation rates).


RESULTS
The rates of survival and fast blastocoele re-expansion of partially intact blastocysts were significantly reduced as compared with fully intact blastocysts. Significantly higher rates of clinical pregnancy (37.1% vs. 16.8%) and implantation (26.7% vs. 11.3%) were obtained when all transferred blastocysts had fast re-expanding blastocoele as compared with those transfers without fast re-expanded blastocysts included.


CONCLUSIONS
Our results showed that blastomere loss of thawed blastocyst was associated with a reduced ability to re-expand. As a discriminative morphologic marker of superior embryo viability, a fast re-expanded blastocyst would be given priority for transfer to better utilize the cryopreserved blastocysts.
Shu
Yimin
Y
Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Stanford University Medical Center, Stanford, California 94304, USA.
Watt
Jill
J
Gebhardt
Janice
J
Dasig
Jennifer
J
Appling
Julie
J
Behr
Barry
B
D000328:Adult; D001755:Blastocyst; D049109:Cell Proliferation; D002470:Cell Survival; D015925:Cryopreservation; D046149:Embryo Culture Techniques; D010064:Embryo Implantation; D004624:Embryo Transfer; D005260:Female; D006801:Humans; D011247:Pregnancy; D018873:Pregnancy Rate; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome