[Blastocyst quality criteria]

Area of Science:

• In vitro fertilization (IVF) and embryology
• Reproductive medicine
• Developmental biology

Context:

• Advancements in acellular and sequential culture media have significantly improved embryo development to the blastocyst stage.
• Blastocyst transfer offers advantages in natural embryo selection and suitability for single embryo transfer (SET).
• Previous IVF attempts may have been hindered by suboptimal embryo selection or transfer timing.

Purpose:

• To evaluate the benefits and risks of blastocyst stage embryo transfer.
• To assess the role of prolonged embryo culture in improving IVF outcomes.
• To compare the efficacy of blastocyst transfer on day 5 versus day 6.

Summary:

• New sequential media enhance embryo culture to the blastocyst stage, facilitating natural selection and improving conditions for single embryo transfer (SET).
• Key advantages include reduced multiple pregnancies and overcoming repeated IVF failures through better embryo selection.
• Potential risks involve challenges in selecting a single blastocyst or limited cryopreserved embryo yield with reduced post-thaw survival.

Impact:

• Prolonged embryo culture is beneficial for day 3 embryos with delayed development, enhancing blastocyst transfer success.
• Blastocyst transfer on day 5 appears more effective than on day 6.
• This approach optimizes IVF outcomes by improving embryo selection and increasing the likelihood of successful implantation.