It is most appropriate to put on the IUD 3-7 days after menstruation because the endometrium is in the proliferative stage and there is less vaginal bleeding after the IUD is put on. Avoid heavy physical labor for a week after the IUD to avoid the displacement of the IUD due to heavy physical labor. In addition, one month after IUD resumes menstruation, check the IUD again after the menstruation is completely clean, because the first menstruation is likely to cause a lot of menstruation, too much menstruation may also cause the IUD to shift, so it is recommended to go to the hospital three days after the menstruation is clean to have the position of the IUD checked, and it is recommended to have the position of the IUD checked once a year.