Live birth outcomes following single-step blastocyst warming technique - optimizing efficiency without impacting live...

Area of Science:

• Reproductive Medicine
• Embryology
• Assisted Reproductive Technology (ART)

Background:

• Vitrification and warming protocols are critical for successful cryopreservation of embryos.
• Standard warming (SW) protocols are time-consuming.
• Optimizing warming protocols can improve efficiency in fertility clinics.

Purpose of the Study:

• To compare the efficacy of a single-step (SS) warming protocol versus standard warming (SW) for vitrified blastocysts.
• To evaluate the impact of SS warming on blastocyst survival, expansion, and subsequent clinical outcomes after frozen embryo transfer (FET).

Main Methods:

• A retrospective analysis of 200 vitrified/warmed blastocysts using Fujifilm Warming NX kits.
• Comparison of SW (14-minute protocol) with SS warming (1-minute protocol).
• Evaluation of 752 frozen embryo transfers (FETs) using generalized estimating equation (GEE) models to assess embryologic and clinical outcomes.

Main Results:

• 100% blastocyst survival and no significant differences in re-expansion rates between SS and SW groups.
• No significant differences in implantation, clinical pregnancy, spontaneous abortion, or biochemical pregnancy rates.
• A statistically significant, though small, increase in the odds of multiple gestations with SS warming was observed.

Conclusions:

• Single-step (SS) warming is an efficient and viable alternative to standard warming (SW) for vitrified blastocysts.
• SS warming significantly reduces thawing time without negatively impacting live birth rates or neonatal birth weights.
• The observed increase in multiple gestations warrants consideration when implementing SS warming protocols.