When a fertilized egg lays outside the body cavity of the uterus, it is called ectopic pregnancy, which is conventionally called ectopic pregnancy. 1, chronic tubal inflammation: It can be divided into tubal mucositis and peritubal inflammation, both of which are common causes of tubal pregnancy. 2, tubal dysplasia or functional abnormalities: tubal dysplasia is often manifested as long fallopian tubes, poor development of the base and lack of mucosal cilia. 3, after various birth control measures: tubal birth control, whether by surgical ligation, electrocoagulation, or silicone ring sleeve, etc., may lead to tubal pregnancy if tubal fistula or recanalization is formed. 4, fertilized egg wandering: one side of the ovary ovulation, fertilized egg through the uterine cavity or abdominal cavity to the opposite side of the fallopian tube migration, called fertilized egg wandering. 5.Other: tumors around the fallopian tubes such as uterine fibroids or ovarian tumors can sometimes affect the patency of the tubal lumen and obstruct the fertilized egg.