Table 1. Cryopreservation methods and embryo developmental stages included in published studies.
Author	Year published	Cryopreservation Method (1st step)	Day of 1st cryopreservation	Re-Cryopreservation Method (2nd step)	Day of re- cryopreservation	Day of embryo transfers
Check et al.	2001	slow freezing	1 to 3	slow freezing	3	3
Kumasako et al.	2009	vitrification	1	vitrification	4 or 5	4 or 5
Murakami et al.	2011	slow freezing	1 to 3	vitrification	5	5
Koch et al.	2011	slow freezing	1 to 5	slow freezing / vitrification	3 to 5	_
Lierman et al.	2014	slow freezing	2 or 3	vitrification	6	5
Zheng et al.	2017	slow freezing	3	vitrification	5 to 7	5
Wang et al.	2021	vitrification	5 or 6	vitrification	5 or 6	5
Hallamaa et al.	2021	slow freezing / vitrification	2 or 3	vitrification	__	__
Li et al.	2021	vitrification	3 or 5	vitrification	5	5
Shen et al.	2023	vitrification	3	vitrification	5	5