Jigal Haas1,2, Jim Meriano3, Rawad Bassil3, Eran Barzilay3,4, Robert F Casper3. 1. TRIO Fertility Partners, Division of Reproductive Sciences, University of Toronto, 655 Bay St 11th floor, Toronto, ON, M5G 2K4, Canada. jigalh@hotmail.com. 2. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. jigalh@hotmail.com. 3. TRIO Fertility Partners, Division of Reproductive Sciences, University of Toronto, 655 Bay St 11th floor, Toronto, ON, M5G 2K4, Canada. 4. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Abstract
PURPOSE: A few years ago, we started to use a new freeze-thaw protocol for the frozen embryo transfer cycles. Instead of thawing the embryos 2-4 h prior to the transfer, we started thawing the embryos 20-22 h prior to the transfer. The aim of this study was to compare the pregnancy rate in cases of embryos that continued to develop in the post-thawing culture to that of embryos that did not. METHODS: A retrospective cohort study of blastocyst freeze/thaw cycles vitrified on day 5, thawed and transferred after 20-22 h in the culture, between January 2012 and December 2016. RESULTS: A total of 375 patients were included in the analysis. Two hundred twenty-eight embryos graded as good, 87 graded as fair, and 60 graded as poor embryos were transferred. The clinical pregnancy rate (50% vs. 19.5% vs 3.3% p < 0.01) and the ongoing pregnancy rate (38.5% vs. 13.6% vs 1.7% p < 0.01) were higher in cases of good embryo quality compared with fair and poor-quality embryos, respectively. For good embryos, progressing to a better grade during the culture did not change the clinical pregnancy rate (51.3% vs. 46.2% p = NS) or the ongoing pregnancy rate (38.5% vs. 37.5% p = NS). For fair embryos, progressing to a better grade during the culture resulted in a higher clinical pregnancy rate (25.4% vs 9% p = 0.05). CONCLUSIONS: The development of the fair embryos in the culture has a highly positive impact on the pregnancy rate and this factor should be taken into consideration before deciding how many embryos to transfer.
PURPOSE: A few years ago, we started to use a new freeze-thaw protocol for the frozen embryo transfer cycles. Instead of thawing the embryos 2-4 h prior to the transfer, we started thawing the embryos 20-22 h prior to the transfer. The aim of this study was to compare the pregnancy rate in cases of embryos that continued to develop in the post-thawing culture to that of embryos that did not. METHODS: A retrospective cohort study of blastocyst freeze/thaw cycles vitrified on day 5, thawed and transferred after 20-22 h in the culture, between January 2012 and December 2016. RESULTS: A total of 375 patients were included in the analysis. Two hundred twenty-eight embryos graded as good, 87 graded as fair, and 60 graded as poor embryos were transferred. The clinical pregnancy rate (50% vs. 19.5% vs 3.3% p < 0.01) and the ongoing pregnancy rate (38.5% vs. 13.6% vs 1.7% p < 0.01) were higher in cases of good embryo quality compared with fair and poor-quality embryos, respectively. For good embryos, progressing to a better grade during the culture did not change the clinical pregnancy rate (51.3% vs. 46.2% p = NS) or the ongoing pregnancy rate (38.5% vs. 37.5% p = NS). For fair embryos, progressing to a better grade during the culture resulted in a higher clinical pregnancy rate (25.4% vs 9% p = 0.05). CONCLUSIONS: The development of the fair embryos in the culture has a highly positive impact on the pregnancy rate and this factor should be taken into consideration before deciding how many embryos to transfer.
Authors: Huy H Pham; Trinh M Vu; Chau H Nguyen; Anh H Le; Dung P Nguyen; Toan D Pham; Tuong M Ho; Lan N Vuong Journal: Reprod Med Biol Date: 2022-05-30