The intrauterine device (IUD) is an effective method of contraception. Most women have no problems with their IUD. Once fitted, it can stay in place for several years.
What is an IUD?
An IUD is a small device made from plastic and copper. It was previously known as 'the coil'. It can be placed quite easily into the uterus (womb) by a trained doctor or nurse.
How does the IUD work?
It works mainly by stopping the egg and sperm from meeting. It may also prevent the fertilised egg from attaching to the lining of the uterus. The copper also has a spermicidal effect (kills sperm).
How effective is the IUD?
Modern IUDs are 99% effective or more. This means that up to 1 women in 100 will become pregnant each year using this method of contraception. (Compare this to when no contraception is used. More than 80 in 100 sexually active women who do not use contraception become pregnant within one year.) There are different types of IUD. Older ones were slightly less reliable - about 98% effective.
What are the advantages of the IUD?
Once an IUD is inserted you can forget about contraception. So, unlike the pill, you don't need to think about contraception every day. It does not interfere with sex. It is not a hormonal method so it has no side-effects on the rest of the body. Most women can have an IUD if they wish.
What are the disadvantages of the IUD?
Most women with an IUD have no problems, but the following occasionally occur.
- Periods - some women find that their periods become heavier, longer, or more painful with an IUD. This tends to be in the first few months after insertion, and then often settles. So the IUD may not be suitable if you already have heavy or painful periods. However, painful and heavy periods can still be treated in the same way as in women who don't have an IUD. For example, by taking anti-inflammatory painkillers or other drugs during periods. Also, there is a special IUD called the intrauterine system (IUS). This device is like an IUD, but it also releases a progestogen hormone into the uterus. This is an effective treatment for heavy periods as well as a contraceptive.
- Infection - there is a small risk of an infection of the uterus (pelvic infection). The main risk is within the first 20 days after insertion. A check for infection of the vagina or cervix may be advised before an IUD is inserted. A sample (swab) may be taken and sent for testing. This may include checking for chlamydia infection. The risk of a pelvic infection from a sexually transmitted infection is also greater in women with a IUD. Therefore, an IUD may not be advisable if you have an increased risk of getting a sexually transmitted infection. For example, if you have more than one sexual partner. An IUD is not advisable if you have previously had a pelvic infection.
- Ectopic pregnancy - the chance of becoming pregnant is very small if you use an IUD. However, if you do become pregnant, there is a higher than normal chance that the pregnancy will be ectopic. This means the pregnancy is in the fallopian tube and not in the uterus. This is rare, but serious. See a doctor urgently if you miss a period and develop lower abdominal pain. An IUD is not advisable if you have previously had an ectopic pregnancy.
- Expulsion - rarely the IUD may come out without you noticing.
- Damage - the fitting of an IUD can (rarely) cause damage to the uterus.
How is the IUD fitted?
This is usually done towards the end of a period or shortly after. However, it can be fitted at any time provided that you are certain you are not pregnant. You will need to have a vaginal examination. The doctor or nurse will pass a small instrument into your uterus to check its size and position. An IUD is then fitted. You will be taught how to feel the threads of the IUD so you can check it is in place. It is best to check the threads regularly, for example, once a month just after a period.
