One-step warming technique for vitrified human blastocysts using commercially available thawing solutions.

Area of Science:

• Reproductive Medicine
• Embryology
• Cryobiology

Background:

• Vitrification and warming are critical steps in assisted reproductive technologies (ART).
• Standard multi-step warming protocols are time-consuming and complex.
• Optimizing warming techniques is essential for improving blastocyst survival and pregnancy rates.

Purpose of the Study:

• To evaluate the re-expansion rates and clinical outcomes of a one-step warming technique for vitrified blastocysts.
• To compare the efficacy of one-step warming with the standard multi-step warming technique.
• To assess the effectiveness of three commercially available thawing solutions with the one-step warming method.

Main Methods:

• A retrospective cohort study of 1173 frozen embryo transfers (FET) in women under 42 years old.
• Comparison of one-step warming (n=573) versus multi-step warming (n=600) protocols.
• Analysis of blastocyst re-expansion, survival, and clinical outcomes, including pregnancy rates.

Main Results:

• One-step warming demonstrated significantly higher blastocyst re-expansion rates (92.4%) compared to multi-step warming (86.8%).
• Clinical pregnancy rates were significantly higher with one-step warming (69.3%) versus multi-step warming (61.2%).
• No significant differences in outcomes were observed between the three thawing solutions used in the one-step method.

Conclusions:

• One-step warming is a more effective method for warming vitrified blastocysts than multi-step warming.
• The one-step warming technique yields superior re-expansion and clinical pregnancy rates.
• Commercially available thawing solutions are equally effective when used with the one-step warming protocol.