Effect of Shorter Pretreatment Time on Clinical and Neonatal Outcomes in Human Blastocysts Vitrification after Artificial Shrinkage

² Edinburgh Assisted Conception Programme, Edinburgh Fertility Reproductive Endocrine Center (EFREC), Royal Infirmary of Edinburgh, EH16 4SA Edinburgh, UK

^*Correspondence: xiaodaoivflab@163.com (Liuguang Zhang)
^†These authors contributed equally.

Clin. Exp. Obstet. Gynecol. 2023, 50(9), 197; https://doi.org/10.31083/j.ceog5009197

Submitted: 7 May 2023 | Revised: 27 August 2023 | Accepted: 4 September 2023 | Published: 22 September 2023

This is an open access article under the CC BY 4.0 license.

Abstract

Background: Prolonged pretreatment time may be harmful to frozen embryo’s developmental potential. This study was conducted to evaluate the effect of different equilibration times on the clinical and neonatal outcomes of frozen-warmed blastocyst transfer. Methods: This is a retrospective study based on data collected from our medical records from March 2018 to March 2022 and including a total of 763 expanded blastocysts from 538 warming blastocyst cycles. These cycles were divided into two groups according to the equilibration time: (A) 6–7 minutes, and (B) 9–10 minutes. The survival rate, clinical, and neonatal outcomes were investigated. Results: The survival, implantation, and clinical pregnancy rates of vitrified-warmed shrinkage blastocyst were not different between the two groups. Other variables analyzed including live birth, multiple gestation, and neonatal outcomes were similar between the two groups. Conclusions: The results of this study illustrated that vitrification of artificially collapsed blastocysts with a shorter equilibration time (6–7 minutes) and pre-vitrification is able to lead to similar clinical and neonatal outcomes in patients undergoing assisted reproductive technology (ART).

Keywords

blastocyst vitrification

artificial collapse

exposure to equilibration solution

pregnancy and implantation rates

spontaneous abortion

neonatal outcomes

Funding

2101320319A2003/Medical and Health Research Project of Hainan

Figures

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Fig. 1.

Photographs of AS and laser-assisted hatching of blastocysts. (A) Laser drilling at the cellular junction of the trophectoderm (red arrow) before vitrification (red dot). (B) Blastocyst after AS. (C) A continuous laser beam was emitted tracing the zona pellucida (ZP) (black arrow) to drill a hole in about one fourth of the ZP surface. (D) Blastocyst partly hatched from ZP after about two hours’ culture. AS, artificial shrinkage; ZP, zona pellucida. Magnification is 400 $\times{}$ .

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Clin. Exp. Obstet. Gynecol. Print ISSN 0390-6663 Electronic ISSN 2709-0094