The most accurate signs of embryo transfer failure to implant are vaginal bleeding, abdominal pain, and negative blood HCG. 1. Vaginal bleeding: sometimes there will be a little vaginal bleeding after implantation, but if the embryo does not implant after implantation, i.e., there will be in vitro biochemistry, some women will have a little vaginal bleeding, accompanied by abdominal distension and pain. Generally the bleeding is large, similar to the amount of menstruation, or even more than the amount of menstruation, and sometimes found that membranous tissues are discharged. 2. Abdominal pain: abdominal pain can also occur after embryo transfer without implantation, or even ectopic pregnancy, if the ectopic pregnancy ruptures, there may be tearing pain in the lower abdomen. 3. Negative blood HCG: two weeks after the implantation, the blood test for human chorionic gonadotropin (HCG) is negative, which is the main clinical feature of implantation failure. Embryo transfer has a certain rate of implantation failure, you should adjust your mindset, actively regulate your body, and subsequently take appropriate measures to help you conceive.