Transferring frozen blastocysts usually does not have a 13-day implantation. Blastocysts are mainly the state of preservation of blastocysts, which is somewhat different from fresh blastocysts, and refers to the freezing of embryos after not being transferred in the same month, and then choosing the appropriate time for transfer, which is called frozen blastocyst transfer at the time of transfer. Transfer of frozen blastocysts successfully implanted in 1~2 days of transfer, but there are individual differences. The time to implantation after transfer is relatively longer in some cases. After frozen blastocysts are transferred, they usually start to grow into the uterine lining after the transfer, and you can go to the hospital after 8 days of the transfer to have a blood test to check the value of human chorionic gonadotropin to determine whether the transfer is successful or not. After the transfer, bed rest and exogenous progesterone supplementation are required to maintain the pregnancy. If there is any doubt about whether the frozen blastocysts have been transferred for 13 days, it is recommended to consult a doctor.