It is not possible to determine whether or not 12 days of transferring a blastocyst requires fertility preservation by the HCG value.
After transplantation, blood test for chorionic gonadotropin HCG and ultrasound are needed to clarify whether there is pregnancy, if not, there is no need for fertility preservation; if pregnant, then the value of HCG 150IU/L for 12 days is slightly low, and it is necessary to look at the doubling of the later period.
The reference value of HCG 12 days after blastocyst transfer is usually 200IU/L, and progesterone should preferably be greater than 18ng/ml or more. If the blood HCG value is 150IU/L at 12 days after transfer, you need to follow up the doubling situation, and if the value rises after rechecking, then you may need to do fertility preservation treatment. You can supplement progesterone fertility preservation treatment under the guidance of the doctor.
If there is any abnormality, you should go to the hospital for examination and treatment under the guidance of the doctor.