Clinically speaking, if the progesterone is below 15 mmol/L, it is not recommended to continue the treatment of fetal preservation, especially for the phenomenon that the blood HCG does not double, which does not exclude the possibility of miscarriage, or the embryo stop growing and developing. Even if the treatment is continued, it will lose some meaning and most of the patients will not be successful after the fetal preservation, so it is not recommended. However, it is necessary to make a judgment according to the patient’s specific condition, especially for patients without any clinical symptoms and manifestations, they need to be reviewed regularly, and if it is clear that the embryo is growing well after the fertility treatment, they can also choose to continue the fertility treatment.