The reference value of HCG in the blood should be about 100 IU/L 12 days after the successful transfer of frozen embryos, i.e. the fertilized egg will be laid in about 6-7 days after the union of sperm and egg. After fertilization, the blood will secrete human chorionic gonadotropin, also known as blood HCG, which will double every 48-72 hours in early pregnancy and will change rapidly. In addition to regular monitoring of the doubling of blood HCG, it is recommended to regularly monitor the progesterone and estradiol values, as the level of hormones will reflect the development of the embryo. If the blood HCG value reaches 4000 IU/L or more, gynecological ultrasound examination should be performed to clarify intrauterine or ectopic pregnancy, and after frozen embryo transfer, attention should be paid to rest, nutrition and reasonable diet.