The causes of ectopic pregnancy are as follows: 1. Patients with chronic tubal infection. In women suffering from chronic tubal infection, adhesions occur in the mucosal wrinkles in the wall of the tube, narrowing the lumen. At the same time, due to inflammation and lesions, it also causes defective mucosal cilia in the fallopian tubes and weakened smooth muscle peristalsis in the tube wall, thus making it difficult for the pregnant egg to reach the uterine cavity. 2. Fallopian tube dysplasia or malformation (including tubal bending, spiral shape, double tubal mouth, etc.). The dysgenesis or malformation of the fallopian tubes reduces the function of the tubes in transporting pregnant eggs and makes it difficult for the fertilized eggs to reach the uterine cavity smoothly. 3. Patients with endometriosis. Endometriosis may cause damaged tissue blocks in the fallopian tubes, creating obstacles to the smooth arrival of the fertilized egg in the uterine cavity. 4. Those with pelvic inflammatory disease and swelling in the pelvis. Due to the extrusion and traction of the mass, the position of the uterus or fallopian tubes may shift, change in shape or even lead to structural abnormalities, and these changes sometimes affect the normal arrival of the pregnant egg in the uterine cavity. 5. Post tubal ligation recanalization. The tubal reopening after ligation is not as smooth as before, and the reopening area is often narrow, so the pregnant egg is easily blocked in the narrow part of the tubal. 6. Those who have a history of ectopic pregnancy. Women with a history of ectopic pregnancy have a high probability of having another ectopic pregnancy. The causes of ectopic pregnancy are repeated abortions. The more abortions there are, the greater the chance of ectopic pregnancy.