A little pain in the stomach on the eleventh day of IVF transfer can be considered as pain caused by the embryo’s implantation, but you also need to consider the adverse phenomenon caused by contractions. 1. Embryo implantation: In the process of embryo IVF transfer, the embryo implantation in the endometrium will cause slight adverse reactions, including slight abdominal pain, small amount of vaginal bleeding or regurgitation and nausea, which is a normal phenomenon. It is recommended to take bed rest, adjust the diet and keep the abdomen warm. 2. Contractions: Abdominal pain after implantation may also be caused by abnormal contractions. If the embryo is unstable during the process of implantation or miscarriage after implantation, it will stimulate the uterus to have abnormal contractions, thus causing abdominal pain. If women experience abnormal abdominal pain or other adverse reactions after the implantation, it is recommended that they go to the hospital in time for ultrasound and hormone level checks, and do not take medication without authorization.