4bb blastocysts are good. IVF mainly refers to pregnancy through in vitro fertilization, which is done after ovulation to accomplish artificial insemination. 4BB Blastocyst: It refers to the grade B blastocysts which are raised to 4 days, “4” stands for different expansion stage blastocysts, and “B” is to grade the quality of the inner cell mass and trophoblast cells. 4BB blastocysts belong to the commonly used blastocysts of high quality and good quality, which is a kind of blastocyst that is more common for embryo transfer, and the implantation rate is over 90%. 4BB blastocysts are of good quality and are commonly used in embryo transfer, and are the most common type of blastocysts, with an implantation rate of more than 90%. 3BB blastocyst: moderate quality, suggesting that the fetus grows relatively well in the uterus, but it is recommended that patients usually pay attention to abdominal warmth, appropriate and reasonable exercise, avoiding strenuous exercise, in order to enhance their own resistance, regular rechecks, and do a good job in preserving the fetus. After blastocyst implantation, you should pay attention to rest, keep a good mood, and eat a light diet. Prohibit sexual intercourse within three months and have regular checkups.