intrauterine device

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intrauterine device (IUD) Intrauterine devices have a long and controversial history, with their widespread acceptance being delayed until the later part of the twentieth century. Hippocrates has been credited with using a hollow lead tube to insert pessaries or other objects into the uterus over 2500 years ago, and Arabs and Turks are known to have placed stones in the uteri of their camels to prevent pregnancy while on long journeys. It was not until 1909 that Richter, a German physician, developed a looped aluminum–bronze wire spiral that could be placed in the human uterus. However, his results did not include details of pregnancy rates because of strict laws against birth control measures in place at the time. Twenty years later Grafenburg reported the use of an intrauterine silk suture, and then modified his technique by using a ring wrapped in wire that contained 26% copper. Early IUDs were associated with high rates of pelvic infection, septic abortion, and haemorrhage, particularly as they were also used by some to terminate pregnancies. A number of maternal deaths were attributed to their use and this led them into disrepute amongst both the medical profession and the general population. It was not until the first international conference on IUDs in New York in 1962 that they gained widespread acceptance. They are now the second most commonly used form of reversible contraception worldwide, mainly because they are so popular in China.

Intrauterine devices work primarily as a foreign body stimulating the immune system into producing an excess of leukocytes and prostaglandins. This creates a hostile environment in the uterus and fallopian tubes, making it difficult for fertilization to occur. In addition, the IUD creates a barrier to implantation of an embryo into the endometrium. Because the contraceptive effect may occur after fertilization some women find this form of family planning unacceptable. Most IUDs are now made of a plastic frame, with copper wrapped around them to increase their contraceptive action and therefore reduce the failure rate. Threads are usually attached to the lower end to facilitate removal. They are extremely reliable, with pregnancy rates of less than 1 per 100 women using them for a year. However, they are not very effective at preventing ectopic pregnancies which develop outside the uterine cavity. IUDs can also be used as ‘emergency’ contraception up to 5 days following the calculated date of ovulation.

Coils, as they are commonly known, are not usually recommended for women who have never been pregnant, as they are more difficult to insert and the slightly increased risk of pelvic inflammatory disease (PID) may impair future fertility. They are also unsuitable for women with a recent history of sexually transmitted disease or multiple sexual partners. Women with an abnormally shaped uterus, possibly caused by fibroids, should use a different contraceptive technique as the risks of failure are much higher in this situation.

The recent development of progestogen-releasing IUDs has been an exciting new contraceptive advance. Difficulties associated with older generation coils, such as heavy and sometimes painful periods, promise to be overcome. They have also provided a new treatment option for women with heavy periods who no longer need contraception, perhaps because they have already been sterilized. This type of IUD can be used to oppose the unwanted effects of oestrogen on the endometrium in women receiving hormone replacement therapy (HRT).

Andrew Hextall, and Linda Cardozo

See also contraception.
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in·tra·u·ter·ine de·vice (abbr.: IUD) • n. a contraceptive device fitted inside the uterus and physically preventing the implantation of fertilized ova.