Intrauterine device

An intrauterine device (IUD), also known as an intrauterine contraceptive device (IUCD or ICD) or coil, is a small, often T-shaped birth control device that is inserted into the uterus to prevent pregnancy. IUDs are a form of long-acting reversible contraception (LARC).

The use of IUDs as a form of birth control dates from the 1800s. A previous model known as the Dalkon shield was associated with an increased risk of pelvic inflammatory disease (PID). However, current models do not affect PID risk in women without sexually transmitted infections during the time of insertion.

Although copper IUDs may increase menstrual bleeding and result in painful cramps, hormonal IUDs may reduce menstrual bleeding or stop menstruation altogether. However, women can have daily spotting for several months after insertion, and it can take up to three months for there to be a 90% decrease in bleeding with hormonal IUDs. Cramping can be treated with NSAIDs. More serious potential complications include expulsion (2–5%), uterus perforation (less than 0.7%), and bladder perforation. Levonorgestrel intrauterine devices (LNG-IUDs) may be associated with psychiatric symptoms such as depression, anxiety, and suicidal ideation, particularly in younger users, though evidence remains mixed and further research is needed. IUDs do not affect breastfeeding and can be inserted immediately after delivery. They may also be used immediately after an abortion.

IUDs are safe and effective in adolescents as well as those who have not previously had children. Once an IUD is removed, even after long-term use, fertility returns to normal rapidly. Copper devices have a failure rate of about 0.8%, while hormonal (levonorgestrel) devices fail about 0.2% of the time within the first year of use. In comparison, male sterilization and male condoms have a failure rate of about 0.15% and 15%, respectively. Copper IUDs can also be used as emergency contraception within five days of unprotected sex.

Globally, 14.3% of women of reproductive age and 22.8% of women using contraception use intrauterine contraception according to 2011 data, with high variance in use rates among different countries, such as 34.1% of women in China in 2017. Among birth control methods, IUDs, along with other contraceptive implants, result in the greatest satisfaction among users.