To explore clinical features and treatment of patients with twin ectopic pregnancy in a previous cesarean scar section (TEPC), and review relevant literature.

One TEPC patient admitted to Hangzhou Women′s Hospital on September 24, 2019, who required pregnancy termination was selected as research subject. Clinical data of the patient was collected by retrospective analysis method, and her clinical features, diagnosis and treatment methods were analyzed. With the following key words of " cesarean scar pregnancy" " twin pregnancy" both in Chinese and English, literature related to TEPC were searched from China National Knowledge Infrastructure, Wanfang data knowledge service platform and PubMed database. Literature retrieval time was set from construction of each database to December 31, 2019. Clinical features, diagnosis and treatment methods of TEPC patients in searched literature were summarized. This study was consistent with the World Medical Association Declaration of Helsinki revised in 2013.

①This patient with requirement of pregnancy termination was a 35 years old female who was admitted to the gynecological clinic of our hospital on September 24, 2019 because of " ectopic pregnancy indicated by ultrasound in other hospital" . She was G₆P₂. She still did not have menstruation after the second cesarean section and was unexpectedly pregnant during lactation. It was 8 months after cesarean section on admission. Serum β-human chorionic gonadotropin (hCG) after admission was 18 587 mIU/mL. Results of transvaginal ultrasound showed that her uterus was gourd shaped, and 2.9 cm × 1.7 cm × 1.5 cm and 1.7 cm × 1.6 cm × 1.3 cm mixed echo dark area which were locally protruded to bladder could be found in lower part of uterus, thickness of scar muscle layer where gestational sac planted was 0.10 cm. Her gestational age was 6⁺ weeks. On September 26, 2019, she underwent bilateral uterine artery embolization (UEA). And then 24 hours later, she underwent transabdominal ultrasound-guided uterine curettage. The amount of transoperative bleeding was 300 mL. After operation, a 16F air bag urinary catheter was placed in her uterine cavity to stop bleeding. She received detection of serum β-hCG once a week after operation, and her serum β-hCG decreased to <5 mIU/mL on the 63th day after operation. ②According to the literature search strategy set in this study, literature search results showed that a total of 4 TEPC related case reports were retrieved, involving 5 TEPC patients. Among them, 3 cases with small gestational weeks when they were diagnosed as TEPC were treated conservatively with methotrexate, and 2 cases were treated sucessfully, 1 case was treated by hysteroscopic curettage after failure of methotrexate treatment. 1 case was treated by transabdominal curettage due to thin muscle layer at the scar and abundant peripheral blood supply. And 1 case underwent hysteroscopic curettage combined with laparoscopic uterine scar repair. All those 5 patients had a good prognosis.

Early clinical diagnosis of TEPC patients should be based on a comprehensive judgment based on the patient′s medical history, clinical symptoms, and ultrasound examination results. For TEPC patients, individualized treatment options should be formulated according to the patient′s gestational age, thickness of myometrium at the scar of gestational sac implantation, and clinical experience of attending physician, so as to achieve the goal of safe and effective treatment of patients with TEPC.