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An intrauterine device (IUD) refers to one or two different small pieces of equipment that are placed in the uterus by a medical practitioner for the purpose of birth control. Most commonly, an IUD is a tiny copper piece that is shaped like a T. It is one of the most effective birth control methods, for those who tolerate it, and prevents pregnancy through stimulation of mucus production in the cervix and uterus, which forms a barrier to the passage of sperm. A similar product that is newer is a small device that secretes progestin. This may be differentiated from the IUD by name and called an intrauterine system or intrauterine contraception (IUC).
Different types of the IUD have existed for decades. Some early types were not effective, and in particular, in the 1970s the Dalkon Shield resulted in very high numbers of lawsuits because it caused significant risk for developing pelvic inflammatory disease (PID). The Dalkon Shield’s number of lawsuits made many people suspicious of the intrauterine device, but the present types don’t pose similar risks. The two most common kinds available are the copper Paragard® and the progestin-releasing Mirena®.
Insertion of an intrauterine device has to be done by a doctor. Part of the insertion process, especially the "sounding," or measurement of the uterus, is very uncomfortable. The discomfort is quickly over, though some women experience cramping or breakthrough bleeding. Doctors often recommend use of the IUD in either form for women who have undergone pregnancy. There is greater chance the device will be expelled in women who haven’t.
Both forms of intrauterine device have high effectiveness ratings, comparable or better than even the birth control pill of some types, about 97-99.5% effective. They don’t protect against sexually transmitted diseases and are thus most suited to women in committed relationships. There are problems associated with IUDs, which can vary depending on type.
Copper IUDs may cause significant increase in period volume and length, and breakthrough bleeding. IUDs may cause ovarian cysts, especially in the first few months after insertion. There is a slight risk of developing PID, chance of the device being expelled, or small possibility that the IUD will perforate the uterus. An IUC could also cause PID, be expelled or perforate. A very slight chance of pregnancy occurs with either type of IUD, and there is greater likelihood of ectopic pregnancy.
The hormonal intrauterine device is associated with decreased menstrual bleeding. Progestin can’t be used by everyone, and is not recommended for smokers over 35 or people at risk for heart attack or stroke. A common complaint about Mirena® is that it can cause mood changes. Additionally, progestin has been shown to lower sexual interest. IUD placement of either type tends to be expensive and not all insurance companies cover these costs.
Advantages of this form of birth control include its general ease of use. Once in place, women need only check the strings, which hang into the vagina, once a month to verify birth control is working. Most women tolerate the intrauterine device quite well, and if they change plans and want to get pregnant, the device can be quickly removed. Another benefit is the length of time this birth control can be used, up to 10 years for copper IUDs.