You can’t have intercourse before the frozen embryo transfer to avoid causing infection or unwanted pregnancy. 1. Cause infection. Frozen embryo transfer before sex may increase the chance of reproductive tract infection, coitus when the cervix is open, semen into the uterine cavity may cause intrauterine contamination, contamination of the growth environment of the embryo transplantation is not conducive to embryo implantation. In addition, after coitus may also increase the incidence of vaginitis, once infected with inflammation will also affect the frozen embryo transfer. 2. Unexpected pregnancy. Some women may be infertile due to unknown reasons, such as coitus before embryo freezing transfer is likely to cause unwanted pregnancy, in the case of not knowing the pregnancy of embryo freezing transfer, will increase the possibility of multiple pregnancies, women’s health and embryo development are not good. In conclusion, it is recommended to avoid sexual intercourse before embryo transfer to avoid increasing the negative factors affecting embryo transfer.