Abstract: bryos were successfully matched. 3 embryos were transplanted and 2 of them were successfully implanted, but one was implanted at the normal position in the uterus, and the other was implanted at the scar position of the previous cesarean section. The patient was treated with the reduction of the gestation sac at the scar position. Then the patient came to the hospital for treatment because of irregular vaginal bleeding. The gynecological ultrasonography showed that there were 2 fetal sacs in the uterine cavity. The fetal bud and fetal heart of one fetal sac could be seen; the other fetal sac was located at the scar position of the previous cesarean section, and only the fetal sac of irregular shape could be seen while the yolk sac or fetal bud could not be seen. Finally, the fetus was removed by intra-abdominal placenta removal + CSP lesionectomy+ cesarean section scar diverticulum neoplasty, and the pregnancy was terminated. This particular case was reported to compare the advantages and disadvantages of ultrasonography and magnetic resonance imaging (MRI) for diagnosing CSP. Some thoughts on the treatment and prevention of CSP were provided.

Key words: Uterus, Cicatrix, Fertilization in vitro, Embryo transfer, Pregnancy, ectopic, Pregnancy reduction, multifetal, Cesarean scar pregnancy