Related Experiment Video
Updated: May 2, 2026
Modified MicroSecure Vitrification: A Safe, Simple and Highly Effective Cryopreservation Procedure for Human Blastocysts
Published on: March 2, 2017
Single-embryo transfer of vitrified-warmed blastocysts yields equivalent live-birth rates and improved neonatal
Tammie K Roy1, Cara K Bradley1, Mark C Bowman1
1Genea, Sydney, New South Wales, Australia.
Objective:
To compare pregnancy and neonatal outcomes after fresh and vitrified-warmed single-blastocyst transfers.
Design:
Retrospective study.
Setting:
Private in vitro fertilization (IVF) clinic.
Patient(S):
1,209 infertile patients who underwent a total of 1,157 fresh and 645 vitrified-warmed embryo transfers.
Intervention(S):
Day-5 single-blastocyst transfers using fresh or vitrified-warmed (Cryotop method) grade I and grade II embryos.
Main Outcome Measure(S):
Fetal heart pregnancy rate, live-birth rate, gestational age, and live-birth weight.
Result(S):
The overall blastocyst thaw survival rate was 94.4% and was not significantly different between blastocyst grades or developmental stages. Similar clinical outcomes were achieved for fresh and vitrified-warmed blastocyst transfers; for example, grade I blastocysts had a live-birth rate of 52.8% versus 55.3%, respectively, and grade II blastocysts had a rate of 34.9% versus 30.4%, respectively. Significantly improved neonatal outcomes were evident for vitrified-warmed blastocyst transfers for gestational age, being on average 0.3 weeks longer, and for live-birth weight with babies born on average 145 g heavier (3,296 g versus 3,441 g for fresh and vitrified-warmed groups, respectively), as compared with fresh transfers.
Conclusion(S):
Embryo transfer of vitrified-warmed blastocysts yields equivalent live-birth rates and improved neonatal outcomes compared with fresh transfers.
