The IUD stimulates the endometrium, causing an inflammatory reaction in the endometrium, which in turn affects the fertilization of the egg to achieve the purpose of contraception.
The IUD is a foreign body to the lining of the uterus, which will stimulate the lining of the uterus, leading to inflammation of the lining of the uterus, which will cause damage to the lining of the uterus and a large number of phagocytosis cells to gather, which will make it difficult for the fertilized egg to implant, and then achieve the purpose of contraception.
In addition, there are also some birth control rings that may release some chemicals, which have a certain effect on sperm, egg or fertilized egg, resulting in the environment in the uterine cavity is no longer suitable for the combination of sperm and egg or embryo growth and development, which leads to the death of sperm, egg or fertilized egg, resulting in the contraceptive effect.
For more medical knowledge it is recommended to consult a medical professional.