Contraceptive principles of IUDs

At present, the mechanism of IUD is more complicated and not completely clear. Generally speaking, it changes the internal environment of uterus through IUD, that is, it causes special reaction of fallopian tube and uterus. This reaction will not cause pain and harm unless it is very special. After causing reaction of fallopian tube and uterus, it can make male sperm difficult to combine with female egg. In addition, IUDs can cause endocrine changes in the body. Even if sperm and eggs combine, the IUD activates plasminogen and causes the blastocyst formed by the fertilized egg to dissolve. The blastocyst cannot develop into a fetus. If IUDs are placed, follow-up examinations should be paid attention to in case of pregnancy caused by IUD detachment.