The IUD can be placed 3-7 days after menstruation for the following reasons: First, the endometrium is thin during this period, so the IUD can be placed into the uterine cavity to reduce rejection and can be placed in the right position without causing increased bleeding from the uterine cavity. Second, during this period, the ovaries have not yet ovulated, so it can play a very good role in contraception. If a woman does not place the IUD during this period, she may experience increased bleeding from the uterine cavity due to a thicker endometrium, or if she becomes pregnant, the IUD cannot be used as a contraceptive when it is not yet detected. After the IUD is placed, it is also important to take proper rest and give anti-blooding and anti-infection medication for 3 days. You can go to the hospital after your next period to review the position of the IUD in the uterine cavity to avoid any displacement that may lead to accidents.