There are still no unified criteria for the diagnosis of persistent ectopic pregnancy. Combining the different reports on PEP, most studies agree on the rise or abnormally slow fall of postoperative β-HCG as an indication of the presence of trophoblastic hyperplasia. Etiology of persistent ectopic pregnancy: the occurrence of persistent ectopic pregnancy is closely related to the time of menopause, but also to the technique used in the technique. In tubal pregnancy, most of the trophoblasts are confined to the superficial layer of the myometrium of the luminal surface of the fallopian tube, while a few may invade the deep myometrium of the wall, the plasma layer, or even extend outside the fallopian tube or into the blood vessels. In the latter case, even the most meticulous conservative surgery may leave trophoblasts behind. Our multifactorial investigation of the patient’s clinical condition including ectopic pregnancy mass size, location, and β-HCG level revealed that mass diameter and pathology with or without villi were very relevant to the occurrence of this complication and, according to the literature, to the time of menopause, with the younger the gestational age and the smaller the mass, the greater the likelihood of this complication. It is hypothesized that in earlier ectopic pregnancies, there is little clotting and bleeding between the trophoblast and the tubal wall, and no stripping surface has yet formed, making it difficult to remove the pregnancy tissue from the implantation surface. There have also been case reports of this condition occurring when trophoblast cells free in the abdominal cavity can continue to grow ectopically despite removal of the fallopian tube. Risk factors for persistent ectopic pregnancy: early ectopic pregnancy with <42 days of menopause and a mass <2 cm in diameter; lack of a clear demarcation interface between the eroded trophoblast and the tubal implantation site in early ectopic pregnancy, making embryo sac removal more difficult and not easily removed completely; preoperative serum HCG >3000 IU/L or an increase of >100 IU/L per day and progesterone >35.2 nmol/L; history of previous ectopic pregnancy; presence of pelvic adhesions. Diagnosis of persistent ectopic pregnancy: persistent ectopic pregnancy presents with recurrent abdominal pain after ectopic pregnancy, continued intra-abdominal bleeding, pelvic masses, and continued elevation or stagnation of postoperative blood β-HCG. The diagnostic criteria are: continued elevation of postoperative blood β-HCG or blood β-HCG still greater than 25 units/L 2 weeks after surgery or recurrent abdominal pain within 2 weeks after surgery, posterior fornix aspiration of non-coagulated blood and reoperation, and postoperative pathology confirming the continued presence of trophoblast or metaphase tissue in the fallopian tube. It can occur relatively early or late in the postoperative period, usually occurring 1 to 4 weeks postoperatively. Postoperative monitoring of blood β-HCG can help in early diagnosis. The diagnostic criteria for blood β-HCG have not been standardized. Some authors believe that a decrease of <20% every 72h will establish the diagnosis; some authors believe that blood β-HCG should decrease to negative 12d postoperatively, and if it decreases <10%, a high alert for this disorder should occur; some authors believe that preoperative blood β-HCG >3000mIU/ml or postoperative day 2, day 7 > Some authors consider preoperative blood β-HCG >3000mIU/ml or postoperative day 2 and day 7 >1000mIU/ml and progesterone >15ng/ml on day 9 as high-risk factors for the development of this disorder. We believe that most of the chorionic tissue was removed at the time of surgery, the blood β-HCG will drop initially after surgery, and a particular value will not be sufficient to detect all patients, and the blood β-HCG should be monitored to normal value at follow-up. Preventive measures 1. Strictly grasp the surgical indications for conservative surgical treatment before surgery, take a detailed medical history and improve all examinations, pay attention to high-risk factors, and weigh the feasibility and advantages and disadvantages of conservative surgical treatment for early ectopic pregnancy. The surgical approach should be decided according to the patient’s preoperative wishes, the condition of the contralateral fallopian tube and the operator’s surgical proficiency. Laparoscopic conservative surgery for ectopic pregnancy is currently considered to be the best treatment for ectopic pregnancy, but the incidence of persistent ectopic pregnancy is higher than that of laparoscopic surgery, and the failure rate is similar to that of MTX embryo-killing treatment for ectopic pregnancy. 3. Tubotomy is more likely to remove embryonic tissue completely than cystic extrusion, so extrusion of the embryo sac from the cystic end of the fallopian tube should be avoided as much as possible during surgery. It is important to fully remove the pregnancy material during the operation, and to avoid bleeding caused by repeated clamping too deep and severe damage to the fallopian tubes by excessive electrocoagulation. 4. It should be noted that sometimes the true implantation site of the pregnancy is near the uterine end of the dilated part of the fallopian tube. When removing the contents of this area, the near uterine end must be explored and should be examined more carefully when there is bleeding so as not to miss the implantation site. 5. Before incision of the fallopian tube, a total of 5 to 10 units of diluted posterior pituitary hormone is injected into the tubal tract near the umbilicus and the uterine horn, after incision of the fallopian tube, the contraction of the fallopian tube caused by posterior pituitary hormone tends to make the pregnancy and clot in the lumen peel off automatically, and even squeeze out the incision automatically, posterior pituitary hormone can also reduce bleeding and make the wound surface clean, which is helpful to check whether there is residual pregnancy, thus reducing the incidence of PEP. The incidence of PEP is reduced, and the chance of removal of the fallopian tube due to the difficulty of hemostasis is also reduced. 6. Postoperative prophylactic treatment with MTX can reduce the incidence of persistent ectopic pregnancy. To reduce the growth of residual trophoblasts and their implantation elsewhere, careful intraoperative manipulation and thorough irrigation should be performed. Some authors recommend prophylactic single dose of MTX (1 mg/kg) administered within 24 h after conservative surgery for ectopic pregnancy, which can greatly reduce the incidence of this complication and shorten the follow-up period. Some authors have also suggested that patients with relatively high preoperative blood β-HCG and an intact contralateral fallopian tube may be considered for a tubectomy on the affected side. Patients with low and steadily declining blood β-HCG can be treated with expectant therapy; patients with elevated blood β-HCG or stagnant decline without symptoms should strive for treatment with drugs such as MTX, and most patients in our group were successfully treated with drugs; if symptoms appear, surgery should be performed promptly. Depending on the conditions at that time, laparoscopic or open surgery is chosen. Conservative surgery such as tubal ostomy is still feasible, but at this time, the fallopian tubes are often severely damaged and tubectomy is required. Monitoring Postoperative monitoring of blood beta-HCG is essential, at least once or twice a week. Patients with ectopic masses ≤2 cm in diameter or after conservative surgery with menopause <42 d should be on high alert. The presence of villi in postoperative pathology does not exclude the possibility of this condition, and the absence of villi in postoperative pathology should be taken more seriously. Regular hCG measurement is the main means of monitoring, requiring weekly measurement of blood β-hCG levels. The rate of decline in blood β-hCG after successful conservative surgery is not significantly different from that of tubectomy. Most ectopic pregnancies have a 50% lower decline in blood β-hCG after conservative surgery than preoperatively, with a decline to normal by 12 days postoperatively. Patients were also noted for any sudden onset of lower abdominal pain, anal cramping or vaginal bleeding. Persistent ectopic pregnancy has been reported to often present with symptoms such as tubal rupture or internal bleeding within 1 week postoperatively. We believe that conservative surgery is successful if the patient has menstrual flow after 1 month postoperatively.