D. Sakkas et al., Assessment of early cleaving in vitro fertilized human embryos at the 2-cell stage before transfer improves embryo selection, FERT STERIL, 76(6), 2001, pp. 1150-1156
Objective: To determine the most viable embryos for transfer.
Design: Study 1: Preselection of early-cleaving 2-cell embryos for transfer
. Study 2: Alternating weeks during which preselection was performed and no
t performed.
Setting: ART program, Birmingham Women's Hospital, Birmingham, United Kingd
om.
Patient(s): Patients undergoing IVF or ICSI cycles with transfer on day 2.
Intervention(s): Culture of all fertilized embryos.
Main Outcome Measure(s): Number of fertilized embryos cleaving to the 2-cel
l stage on day 1, embryo quality, implantation rates, and pregnancy rates.
Result(s): Patients with early-cleaving 2-cell embryos had significantly hi
gher 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 wh
ich preselection was used. the overall pregnancy and implantation rates of
the clinic improved.
Conclusion(s): The presence of early-cleaving 2-cell embryos improves a pat
ient's chance of achieving pregnancy. Use of more stringent embryo selectio
n criteria can improve overall pregnancy rates. (Fertil Steril (R) 2001-,76
:1150-6. (C) 2001 by American Society for Reproductive Medicine.).