There are two main types of IUDs: inert and active rings, which are suitable for women of childbearing age who have no contraindications and require placement. The placement time is 3~7 days after menstruation, 3 months after natural delivery or 6 months after cesarean section, and after spontaneous abortion and mid-term induced abortion. 1. Inert ring: made of inert material, which has been discontinued due to its high rate of dislodgement and pregnancy with device and low rate of continued storage. 2. Active ring: (1) with copper T-shaped ring: models 200, 220, 250, 300, 380, etc.. (2) V-shaped ring with copper. (3) Y-shaped ring containing progesterone. (4) Others: zinc-containing, magnetic, prostaglandin synthase inhibitors and antifibrinolytic drugs. 3. Contraindications to IUD placement: genital inflammation, uterine fibroids and uterine deformities, excessive or irregular menstruation, loose cervical opening, anemia and serious heart, liver, kidney and other systemic diseases. IUD need to go to the regular hospital by a professional physician according to their own situation for placement, not randomly and blindly placed.