section_path: Methods/Intrauterine devices
section_name: Intrauterine devices
paragraph_text: Intrauterine devices
  
  The current intrauterine devices (IUD) are small devices, often T-shaped, containing either copper or levonorgestrel, which are inserted into the uterus. They are one form of long-acting reversible contraception which are the most effective types of reversible birth control. Failure rates with the copper IUD is about 0.8% while the levonorgestrel IUD has a failure rates of 0.2% in the first year of use. Among types of birth control, they, along with birth control implants, result in the greatest satisfaction among users. As of 2007, IUDs are the most widely used form of reversible contraception, with more than 180 million users worldwide.
  
  Evidence supports effectiveness and safety in adolescents and those who have and have not previously had children. IUDs do not affect breastfeeding and can be inserted immediately after delivery. They may also be used immediately after an abortion. Once removed, even after long term use, fertility returns to normal immediately.
  
  While copper IUDs may increase menstrual bleeding and result in more painful cramps, hormonal IUDs may reduce menstrual bleeding or stop menstruation altogether. Cramping can be treated with painkillers like non-steroidal anti-inflammatory drugs. Other potential complications include expulsion (2–5%) and rarely perforation of the uterus (less than 0.7%). A previous model of the intrauterine device (the Dalkon shield) was associated with an increased risk of pelvic inflammatory disease; however, the risk is not affected with current models in those without sexually transmitted infections around the time of insertion. IUDs appear to decrease the risk of ovarian cancer.