A fertilized egg that lays outside the body cavity of the uterus is called ectopic pregnancy, which is commonly referred to as ectopic pregnancy. These include tubal pregnancy, ovarian pregnancy, abdominal pregnancy, broad ligament pregnancy, and cervical pregnancy. Among them, tubal pregnancy is the most common, accounting for about 95%. Here we will mainly understand how tubal pregnancy is caused. 1. Inflammation Inflammation of the fallopian tubes is the main cause of tubal pregnancy. For example, infection of the female reproductive tract with Neisseria gonorrhoeae and Chlamydia trachomatis often causes mucositis of the fallopian tubes, resulting in adhesion of the mucosal folds, narrowing of the lumen, or impairment of the cilia function, which leads to obstruction of the fertilized egg in the fallopian tubes and its implantation in the fallopian tubes; infection after abortion and childbirth often causes peritubal inflammation, resulting in adhesion around the fallopian tubes, distortion of the fallopian tubes, weakened peristalsis, which affects the operation of the fertilized egg and its implantation in the fallopian tubes The tuberculosis bacillus causes infection of the reproductive tract, and the mucosa of the fallopian tube extends into the muscular wall in a diverticulum-like manner, and nodular hyperplasia occurs in the muscular wall, which prevents the fertilized egg from running and implanting in the fallopian tube. 2. History of tubal surgery: Tubal pregnancy may occur due to tubal fistula or tubal recanalization after conservative tubal surgery, such as tubal window retrieval, tubal ligation or tubal plastic surgery. 3, tubal dysplasia or functional abnormalities Very few women have congenital abnormalities of the fallopian tubes, such as overgrown fallopian tubes, poorly developed muscular layer or lack of mucosal cilia, which can cause tubal pregnancy. 4, contraceptive failure The failure of intrauterine device contraception or oral contraceptive pill contraception has a greater chance of ectopic pregnancy. Tumor compression Uterine fibroids or ovarian tumors compress the fallopian tubes, affecting the patency of the lumen and obstructing the operation of the fertilized egg, thus causing tubal pregnancy.