Ectopic pregnancy refers to the implantation of a fertilized egg outside the uterine cavity, among which tubal pregnancy is the most common type, accounting for about 95% of ectopic pregnancies. There are many causes of ectopic pregnancy, with the main cause being inflammation of the fallopian tubes. The inflammation can cause the mucous membrane of the fallopian tube to become sticky, narrowing the lumen of the tube, or impairing the function of the cilia inside the tube, leading to obstruction of the fertilized egg's movement within the tube and resulting in implantation at that location. Other causes include surgery on the fallopian tubes, poor development or abnormal function of the fallopian tubes, further development of assisted reproductive technologies, and the use of emergency contraceptive pills, also known as contraceptive failure, among others. (The use of medications should be under the guidance of a doctor.)