The blastocyst cannot be detected on the sixth day and in general whether the blastocyst can be detected or not depends on the method of detection. For intrauterine pregnancies, the embryo needs to be examined by ultrasound at around 5-6 weeks of menopause to be able to measure the size of the embryo, and if an abdominal ultrasound is performed it should be detected at around 6-7 weeks of menopause. The appearance of blastocysts is also determined by the speed of their development and growth depending on the length of the woman’s menstrual cycle, but no later than two months. For in vitro fertilization embryo transfer, the time to check the transferred blastocyst is about 15 days after the transfer. You can test the HCG by means of early pregnancy test or blood sampling to be able to determine whether the pregnancy is successful or not, and then perform an ultrasound about one month after the transfer to determine whether the pregnancy is intrauterine or not, and pay attention to rest after the successful conception to reduce the chance of miscarriage.