Progesterone greater than 40 is not suitable for frozen embryo transfer. The normal value of progesterone is between 20-30ng/ml and in practice frozen embryo transfer has a greater success rate. This is because IVF transfer has a high success rate during ovulation, when the hormones in a woman’s body are supportive and suitable for conception. If the progesterone is greater than 40ng/ml, it means that the ovulation period has passed and entered the luteal phase. The hormones in the woman’s body will change accordingly and the environment is unstable, so it is not suitable for transplantation. Even if the transfer is reluctant, it is difficult to succeed. In addition, when transferring frozen embryos, the higher the progesterone is not the better. Progesterone greater than 40ng/ml may affect the endometrial sensibility, which may lead to failure of implantation. If the progesterone before transfer is slightly higher than normal, you can choose to transfer frozen embryos, but greater than 40ng/ml, you can do conditioning before transfer. The specific situation also needs to be under the guidance of the doctor.