Assessment of early cleaving in vitro fertilized human embryos at the 2-cell stage before transfer improves embryo selection.
OBJECTIVE
To determine the most viable embryos for transfer.


METHODS
Study 1: Preselection of early-cleaving 2-cell embryos for transfer. Study 2: Alternating weeks during which preselection was performed and not performed.


METHODS
ART program, Birmingham Women's Hospital, Birmingham, United Kingdom.


METHODS
Patients undergoing IVF or ICSI cycles with transfer on day 2.


METHODS
Culture of all fertilized embryos.


METHODS
Number of fertilized embryos cleaving to the 2-cell stage on day 1, embryo quality, implantation rates, and pregnancy rates.


RESULTS
Patients with early-cleaving 2-cell embryos had significantly higher pregnancy and implantation rates (45 of 100 [45.0%] and 58 of 219 [25.5%], respectively) than did patients without early-cleaving 2-cell embryos (31 of 130 [23.8%] and 43 of 290 [14.8%], respectively). In weeks during which preselection was used, the overall pregnancy and implantation rates of the clinic improved.


CONCLUSIONS
The presence of early-cleaving 2-cell embryos improves a patient's chance of achieving pregnancy. Use of more stringent embryo selection criteria can improve overall pregnancy rates.
Sakkas
D
D
Assisted Conception Unit, Birmingham Women's Hospital, Edgbaston, Birmingham, United Kingdom. Denny.Sakkas@yale.edu
Percival
G
G
D'Arcy
Y
Y
Sharif
K
K
Afnan
M
M
D000328:Adult; D004624:Embryo Transfer; D005314:Embryonic and Fetal Development / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011247:Pregnancy; D020554:Sperm Injections, Intracytoplasmic / Q000379:methods; D013997:Time Factors