Key facts
- An intrauterine device (IUD) is a small, flexible device placed in the uterus to prevent pregnancy.
- Two main types exist: copper-bearing IUDs (non-hormonal) and levonorgestrel-releasing IUDs (hormonal).
- Both types are highly effective, with fewer than 1 pregnancy per 100 women in the first year of use.
- Copper IUDs can prevent pregnancy for up to 10–12 years depending on the product. Hormonal IUDs last for 3–8 years, depending on the type.
- Fertility returns immediately after removal.
- IUDs do not protect against sexually transmitted infections (STIs), including HIV. Condom use is recommended if there is risk of exposure.
- A copper IUD can also be used as emergency contraception if inserted within 5 days of unprotected intercourse.
Overview
IUDs are among the most effective, long-term, and reversible methods of contraception. They are small devices that a trained health-care provider places into the uterus. Once inserted, they provide continuous, long-lasting protection without requiring any daily action from the user.
A copper IUD prevents pregnancy by releasing copper ions that interfere with sperm movement and egg fertilization. It is more than 99% effective as a long-term contraceptive and is also the most effective form of emergency contraception when inserted within 5 days of unprotected sex. The hormonal IUD releases a small amount of levonorgestrel, which thickens cervical mucus, inhibits sperm, and thins the uterine lining. Hormonal IUDs are highly effective as ongoing contraception.
IUDs must be inserted by a trained health worker. The procedure usually takes only a few minutes. The provider places a speculum in the vagina, cleans the cervix, and gently inserts the device through the cervix into the uterus using a thin applicator. Some women feel cramps or discomfort during the procedure, which is typically quick and easy. Otherwise, selected medications may be used to ease insertion. Once in place, the IUD has small strings that extend into the vagina, which can be checked by the woman or her provider to make sure the device is still in place.
Effectiveness
IUDs, both copper and hormonal, are among the most effective contraceptives available. With both typical and correct use, fewer than 1 pregnancy per 100 women occurs in the first year of use. A copper IUD inserted within 120 hours (5 days) after unprotected sex is more than 99% as effective as emergency contraception.
Health benefits and risks
IUDs provide years of reliable contraception and are suitable for women of all ages, including adolescents. They can also be used immediately after childbirth or abortion if clinically appropriate. Copper IUDs are hormone-free, making them an option for women who cannot or do not want to use hormonal methods. Hormonal IUDs can reduce heavy menstrual bleeding and cramps and are sometimes prescribed to manage menstrual disorders.
Some women using copper IUDs may experience heavier or longer periods and stronger cramps, especially in the first few months. Hormonal IUDs may cause lighter periods or no bleeding at all after some months of use. These changes are not harmful but can lead some women to discontinue the method.
Rare but possible risks include perforation of the uterus during insertion, expulsion of the device, and pelvic infection shortly after insertion, usually if there is an untreated STI at the time. Both types of IUDs are safe for breastfeeding women and do not affect milk supply.
IUDs do not cause infertility. Fertility returns immediately after removal. They do not move to other parts of the body. They do not cause birth defects or harm an existing pregnancy. IUDs are safe for both younger and older women.
WHO response
WHO’s recommendations on IUDs are available in the Medical eligibility criteria for contraceptive use 6th ed. and Selected practice recommendations for contraceptive use, 4th ed. This document and its derivative products and tools guide family planning providers in recommending safe and effective contraception methods for women with medical conditions or medically-relevant characteristics; and explain how to use them correctly and safely. Further, WHO has developed a family planning handbook, which offers technical information to help health-care providers deliver family planning methods appropriately and effectively.
These resources help ensure safe use, informed choice, and broad access without unnecessary barriers. WHO also supports integration of contraceptive services into broader sexual and reproductive health care, ensuring that all people can access the method that best suits their needs.