An IUD, or intrauterine device, is a small, T-shaped piece of plastic inserted into the uterus. It prevents pregnancy by altering the cervical mucus, making it difficult for sperm to reach an egg. IUDs are long-lasting, easily removable, and 99% effective at preventing pregnancy. However, insertion can be painful and many clinics do not offer pain reduction methods such as localized anesthesia or medication.
 

There are 2 kinds of IUDs: Hormonal and copper. Hormonal IUDs, which last 5-10 years, release small doses of progestin. As a result, those using IUDs often have lighter menstrual periods or even no periods. However, increased cramping and spotting are common for 3-6 months after insertion. Copper IUDs, which can last up to 12 years, have a thin copper wire wrapped around the plastic “T,” creating a hostile environment for sperm. Side effects of the copper IUD can include pain and bleeding during menstruation and increased spotting when the IUD user is not menstruating. These side effects cause 15% of copper IUD users to get the device removed within a year of insertion.
 

IUDs are also highly effective as emergency contraception. If an IUD is inserted up to 5 days after unprotected sex, it is 99% effective at preventing pregnancy. After, a user can keep it and continue to use it as regular contraception.