Transplantation of blastocysts may cause ectopic pregnancy, the common situations are as follows: 1, if the embryo accidentally swims into the fallopian tube during the continuous swimming, ectopic pregnancy will be formed, generally injecting the blastocysts into the uterine cavity, the blastocysts will stray in the uterine cavity for 3-4 days, slowly find the suitable place of implantation, and then begin to implantation and pregnancy; 2, the process of injecting the blastocysts may cause the contraction of the uterus, in which case the blastocysts may be pushed into the fallopian tubes, which may cause ectopic pregnancy; 3, the injection of blastocysts into the tubes during the process of losing to the fallopian tubes may cause ectopic pregnancy, but this situation occurs too low.