Copper IUD (inter-uterine device)

The information on this page describes the conventional copper IUD. A new form of IUD, called Mirena, has recently become available in Canada. It is inserted into the uterus like other IUDs, but it also contains a hormone to increase its effect.

IUDs are small devices that fit inside the uterus to prevent pregnancy. IUDs available in Canada are made of copper and plastic and shaped like a T. There are several theories of how they work, but we believe that they prevent sperm from fertilizing an egg. To a lesser degree, they may also prevent a fertilized egg from attaching to the wall of the uterus. If there are no complications, an IUD can be left in place from two to five years. They are 96 to 98 percent effective against pregnancy but they do not protect you and your partner against sexually transmitted infections. Women with the following conditions should not use a copper IUD:

• currently pregnant
• allergic to copper
• large fibroids or uterine cancer
• weakened immune systems
• heavy periods or severe cramps (this does not apply to Mirena)
• unusual undiagnosed bleeding from the vagina
• have had recent or chronic pelvic infections
• current vaginal or cervical infection
• women who are at increased risk of sexual transmitted infections

How an IUD is inserted

An IUD must be inserted in a doctor's office or clinic. It is often inserted during your period or shortly after having an abortion or giving birth to ensure that you are not pregnant. An IUD may also be used as emergency contraception by inserting it five to seven days after unprotected intercourse.

The insertion takes about five minutes. It is inserted into the uterus so that thin strings attached to the base of the T hang down through the cervical opening. These strings are trimmed so they are just long enough for you to check that the IUD is in place and so that a health care provider can use them to remove the IUD at a later date. Most women have some cramps when the IUD is being inserted.

You may want to use another method of birth control as back-up for a month in case the IUD moves or comes out. After six weeks, return to your doctor or clinic for a check-up then continue to have your regular check-ups. You should check for the IUD strings each month after your period is over.

Call your doctor or clinic if you:

• can not feel the strings
• feel the tip of the IUD protruding when you do your monthly check
• miss a period or think you may be pregnant
• have unusual cramping, pain or bleeding
• have a vaginal discharge that seems different or has a different odour
• your IUD comes out

The IUD can be easily removed if any of these problems occur or if you wish to get pregnant.

Advantages

• very effective
• inexpensive (copper)
• can be rapidly reversed if you wish to get pregnant
• neither partner can feel an IUD during sex
• the woman controls this method of birth control
• can remain in place for many years
• does not cause any hormonal changes in your body

Disadvantages

• your periods may be longer or heavier (copper)
• you may have increased cramping (copper)
• does not protect against sexually transmitted infections
• if this method fails and pregnancy occurs, it is more likely to be an ectopic pregnancy
• increased risk of pelvic infection mainly associated with insertion
• rarely an IUD may puncture the wall of the uterus