Tubal pregnancy is the most common type of ectopic pregnancy, which is mainly related to tubal abnormality. 1. Chronic tubal inflammation, such as tubal mucositis, causing complete blockage or partial blockage of the fallopian tubes; peritubal inflammation leading to twisting and deformation of the fallopian tubes, which affects the normal transportation of fertilized eggs in the fallopian tubes. 2. History of tubal pregnancy or surgery, previous tubal pregnancy undergoing conservative surgery, and history of tubal sterilization and surgery. 3. Tubal dysplasia or dysfunction, if there is tubal muscular dysplasia, tubal lengthening, lack of mucosal cilia in the tubes, or the presence of tubal diverticulum, etc., tubal pregnancy is likely to occur. 4. Failure of contraception, the peristalsis of the fallopian tube wall, the cilia movement and the secretion function of the epithelial cells are regulated by estrogen and progesterone, such as hormonal balance imbalance after taking emergency contraceptive pills, tubal pregnancy may occur due to the impact on the transportation of the pregnant egg. 5. Others, uterine fibroids or ovarian cysts compressing the fallopian tubes, endometriosis, or congenital anomalies, resulting in slowing down of peristalsis of the fallopian tubes, so that the fertilized egg can not reach the normal uterine cavity and is deposited in the tubal area.