There are no specific statistics on the chances of a successful 5aa blastocyst transfer, and its success rate is relatively high. 5aa blastocysts are high quality blastocysts, meaning that high grade blastocysts that have developed to stage 5, with dominant inner cell mass and trophectoderm, are preferred for transfer. Blastocysts of better quality have a relatively higher chance of successful transfer. There are relatively more factors affecting the success of blastocyst implantation, such as endometrial lining is too thin, having a longitudinal uterus or uterine adhesions, having luteal insufficiency or thyroid function abnormality, immune function abnormality, coagulation abnormality and so on, which may affect the success rate of this implantation. So if you are planning to do IVF, you need to do a series of medical checkups before the transfer so that you can increase the chance of successful blastocyst transfer. It is recommended to consult a professional doctor for details.