Related Experiment Video
Updated: Oct 19, 2025
Single Cell Collection of Trophoblast Cells in Peri-implantation Stage Human Embryos
Published on: June 12, 2020
Thawing day 3 embryos and culturing to day 5 may be a better method for frozen embryo transfer
Roni Rahav-Koren1,2, Shmuel Inbar3,4, Netanella Miller3,4
1IVF Unit, Department of Obstetrics and Gynecology, Meir Medical Center, 59 Tchernichovsky St, 4428164, Kfar Saba, Israel. rahav.roni@gmail.com.
Purpose:
Does thawing cleavage embryos and culturing them for transfer as blastocysts improve pregnancy and perinatal outcomes compared to transferring thawed blastocysts?
Methods:
Retrospective, observational cohort study performed at two assisted reproductive technology centers, 2014 to 2020. A total of 450 patients with 463 thawed embryo transfer cycles were divided into 2 groups according to the embryonic developmental stage at cryopreservation and transfer: 231 thawed blastocysts (day 5 group) and 232 thawed cleavage embryos that were cultured for 2 days and transferred as blastocysts (day 3-5 group). The two groups were compared for demographics, routine parameters of IVF treatment, pregnancy rates, and perinatal outcomes.
Results:
Multivariable logistic regression analysis for ongoing pregnancy and delivery demonstrated that the day 3-5 group had a greater likelihood of achieving ongoing pregnancy and delivery compared to the day 5 group (OR 1.58, 95%CI 1.062-2.361, p = 0.024). Perinatal outcomes were comparable between the three groups.
Conclusion:
Our results support culturing post-thaw cleavage embryos for 2 days and transferring them as blastocysts to increase chances of ongoing pregnancy and delivery.
