Ectopic pregnancy refers to the implantation of a fertilized egg outside the uterine cavity, with tubal pregnancy being the most common type, accounting for up to 95% of cases. There are many causes of ectopic pregnancy, with the main reasons including the following: First, inflammation of the fallopian tubes is a major cause of ectopic pregnancy because the inflammation can cause the mucous membranes of the tubes to adhere, narrowing of the lumen, or impairment of the cilia function, leading to obstruction of the fertilized egg's movement within the tube, preventing it from reaching the uterine cavity, thus, it implants in the tube. Second, the patient has a history of fallopian tube surgery or a previous ectopic pregnancy. Third, poor development or abnormal function of the fallopian tubes. Fourth, the implementation of assisted reproductive technology. Fifth, the intake of emergency contraceptive pills by individuals who experienced contraceptive failure. (The use of medications should be done under the guidance of Doctor Yan.)