Articles Vol. 67 No. 4 25/04/2026

PREGNANCY OUTCOMES IN SINGLE FROZEN BLASTOCYST CYCLES AFTER THAWING AND CULTURING FOR AN ADDITIONAL 16-20 HOURS

Mai Trong Hung1,2, Nguyen Thi My Dung1,2, Nguyen Thi Phuong Mai1,2, Nguyen Thi Linh1,2, Dao Lan Huong1,2, Le Thi Kim Chinh1,2, Nguyen Thi Hang1,2
1 Hanoi Obstetrics and Gynecology Hospital
2 Bệnh viện Phụ Sản Hà Nội
DOI: 10.52163/yhc.v67i4.4884
14 Views
6 Downloads
Keywords
Overnight culture, pregnancy rate, implantation rate, post-thaw culture duration.
Abstract

Objective: To evaluate whether prolonged post-thaw culture duration (16-20 hours) affects the development of embryos  and pregnancy outcomes in single frozen blastocyst transfer cycles.

Methods: This retrospective study included 263 single frozen-thawed day 5 blastocyst transfer cycles between January 2021 and December 2023 at the Department of Assisted ReproductiveTechnology & Andrology, Hanoi Obstetrics and Gynecology Hospital. Blastocyst had blastocoel expansion stage from 1 to 3 before freezing and cultured 16-20 hours after thawing until embryo transfers. The main outcomes were the blastocyst morphology parameters-expansion, inner cell mass (ICM), trophectoderm grade (TE) and the pregnancy rate, implantation rate.

Results: After 16-20 hours of culture, embryos with blastocoel expansion from stage 1 to stage 3 showed development in both the degree of blastocoel expansion and the quality of the ICM and TE. Stage 1 embryos could progress to stages 2-4 (69.7%), stage 2 embryos developed to stages 3-5 (90%), and stage 3 embryos progressed to stages 4-6 (67.5%). The ICM and TE could be evaluated more clearly. The pregnancy rate was 66.9%, and the implantation rate was 57.5%. Embryos developing to stages 4 and 5 had the best outcomes.

Conclusions: A 16-20 hour post-thaw culture can be applied to embryos with blastocoel expansion stages from 1 to 3 to enhance embryo development, allow better assessment of embryo quality, and improve the prediction of embryo transfer outcomes.

References
[1]
Edgar D.H, Bourne H, Speirs A.L et al. A quantitative analysis of the impact of cryopreservation on the implantation potential of human early cleavage stage embryos. Hum Reprod Oxf Engl, 2000, 15 (1): 175-179. Google Scholar
[2]
Fang C, Yue C.M, Huang R et al. Pregnancy outcomes of blastocysts cultured overnight after thawing. Arch Gynecol Obstet, 2016, 293 (6): 1347-1356. Google Scholar
[3]
Haas J, Meriano J, Bassil R et al. Prolonged culture of blastocysts after thawing as a tool for improving prediction of success. J Assist Reprod Genet, 2018, 35 (12): 2195-2199. Google Scholar
[4]
Harrity C, Vaughan D, Emerson G et al. Effect of blastocyst stage and grade on successful embryo transfer. Fertil Steril, 2013, 100 (3): 288. Google Scholar
[5]
Yu Q, He H, Ren X et al. Pregnancy outcomes for day 5 versus day 6 single frozen-thawed blastocyst transfer with different qualities of embryos: a large matched-cohort study. Curr Med Sci, 2023, 43 (2): 297-303. Google Scholar
[6]
Dimitriadis I, Christou G.Y, Dickinson K.A et al. Optimal day to thaw day 5 vitrified blastocysts for frozen embryo transfers. Fertil Steril, 2017, 107 (3): 41-42. Google Scholar
[7]
Ahlstrom A, Westin C, Wikland M et al. Prediction of live birth in frozen-thawed single blastocyst transfer cycles by pre-freeze and post-thaw morphology. Hum Reprod, 2013, 28 (5): 1199-1209. Google Scholar