Related Experiment Video
Updated: Jun 14, 2026
Minimally Invasive Embryo Transfer and Embryo Vitrification at the Optimal Embryo Stage in Rabbit Model
Published on: May 16, 2019
Can fresh embryo transfers be replaced by cryopreserved-thawed embryo transfers in assisted reproductive cycles? A
Abbas Aflatoonian1, Homa Oskouian, Shahnaz Ahmadi
1Research and Clinical Center for Infertility, Department of Obstetrics and Gynecology, Shahid Sadoughi University of Medical Science, Safaieh, Yazd, Iran. abbas_aflatoonian@yahoo.com
Purpose:
Controlled ovarian hyperstimulation has been shown to advance endometrial maturation and adversely affects implantation in ART. It has been reported that there is a better embryo-endometrium synchrony in frozen-thawed embryo transfer cycles than fresh embryo transfer cycles. The objective of this study was to compare ongoing pregnancy rates between fresh ET and FET cycles.
Methods:
In an open prospective, controlled study, the patients who were classified as high responders, were randomized to either fresh ET or FET. The embryos in FET group were cryopreserved with vitrification by Cryotop method.
Results:
A total of 374 patients were included, 187 of which were randomized to FET and 187 to fresh ET. There were 39% (n = 73) ongoing pregnancy in FET group compared with 27.8% (n = 52) in fresh ET group[odds ratio = 1.66;95% confidence interval = 1.07-2.56; p = 0.02].
Conclusions:
FETs can be performed instead of fresh ETs to improve the outcome of ART in highly selected patients.
