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An intrauterine device (IUD or coil) is a small contraceptive device, often 'T'-shaped, often containing either copper or levonorgestrel, which is 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 rate 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 NSAIDs.〔 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.〔(【引用サイトリンク】title= Popularity Disparity: Attitudes About the IUD in Europe and the United States )〕 ==Types== The types of intrauterine devices available and the names they go by differ by location. In the United States, there are two types available: *Nonhormonal copper IUD (ParaGard) *IUD with progestogen (Mirena among others) The WHO ATC labels both copper and hormonal devices as IUDs. In the United Kingdom, there are over 10 different types of copper IUDs available. In the UK, the term IUD refers only to these copper devices. Hormonal intrauterine contraception is considered to be a different type of birth control and is labeled with the term intrauterine system (IUS). ===Copper=== (詳細はParagard TCu 380a measures 32 mm (1.26") horizontally (top of the T), and 36 mm (1.42") vertically (leg of the T). Copper IUDs are becoming increasingly popular because they are more resistant to corrosion. In the "Eurogine Gold T IUD.〔http://www.eurogine.com〕", which is made in Spain, there is a gold core, which further prevents the copper from fragmenting or corroding. GoldringMedusa is a differently-shaped German version of the Gold T.〔http://www.viomed.de/de/medusa〕 Another form of AuCu IUD is called Goldlily which is made by the Hungarian company, Radelkis. Goldlily consists of a layer of copper wires wrapped around an original layer of gold wires, and it provides electrochemical protection in addition to ionic protection.〔http://www.radelkis.hu/en/orvos/huv/frames.html〕 Silver IUDs also exist. Radelkis also makes Silverlily, which is similar to Goldlily, and GoldringMedusa is available in an AgCu version as well. Nova-T 380 contains a strengthening silver core, but does not incorporate silver ions themselves to provide electrochemical protection. 〔 Other shapes of IUD include the so-called U-shaped IUDs, such as the Load and Multiload, and the frameless IUD that holds several hollow cylindrical minuscule copper beads. It is held in place by a suture (knot) to the fundus of the uterus. It is mainly available in China, Europe, and Germany, although some clinics in Canada can provide it. A framed copper IUD called the IUB SCu300A coils during deployment to form a three dimensional spherical shape and is based on a shape memory alloy core. Advantages of the copper IUD include its ability to provide emergency contraception up to five days after unprotected sex. It is the most effective form of emergency contraception available. It works by preventing fertilization or implantation; however does not affect already implanted embryos. It contains no hormones, so it can be used while breastfeeding, and fertility returns quickly after removal. Copper IUDs are also available in a wider range of sizes and shapes than hormonal IUDs. Disadvantages include the possibility of heavier menstrual periods and more painful cramps. In addition to copper, noble metal and progestogen IUDs, patients in China can get copper IUDs with indomethacin. This non-hormonal compound reduces the severity of menstrual bleeding, and these coils are popular. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Intrauterine device」の詳細全文を読む スポンサード リンク
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