From the Research
In embryo grading for IVF, a 4AA embryo is generally considered the highest quality among the options listed (4AA, 3AB, 3BB, 4BB, 4BC) due to its advanced stage of expansion and excellent quality inner cell mass and trophectoderm cells, as supported by the most recent study on embryo transfer and implantation rates 1. The grading system typically uses numbers to indicate blastocyst expansion (with higher numbers being more expanded) and letters to indicate the quality of the inner cell mass (first letter) and trophectoderm cells (second letter), with A being the highest quality, followed by B and then C. Some key points to consider in embryo grading and transfer include:
- The importance of embryo quality, as well as endometrial quality, in determining the success of implantation, as discussed in a recent study on resolving recurrent implantation failure 2.
- The use of ultrasound guidance, catheter design, and transfer technique to improve the probability of embryo implantation, as described in a study on embryo transfer 3.
- The potential for "lower grade" embryos to still result in healthy pregnancies, highlighting the need for individualized consideration of embryo selection decisions, as noted in a study on the rate of true recurrent implantation failure 1. However, it's essential to prioritize the most recent and highest quality study, which suggests that true recurrent implantation failure is rare, and that the cumulative live birth rate after up to three consecutive frozen euploid single embryo transfers is 92.6% 1. Key factors influencing embryo selection decisions include:
- Maternal age
- Embryo genetic testing results
- Overall health considerations Ultimately, the decision on which embryo to transfer should be made in consultation with a fertility specialist, taking into account the individual circumstances and priorities of the patient.