Intrauterine device (IUD) for birth control

Treatment Overview

The intrauterine device (IUD) is a long-term birth control method. Unlike IUDs that were used in the 1970s, present-day IUDs are small, safe, and highly effective.¹

An IUD is a small, T-shaped plastic device that is wrapped in copper or contains hormones. The IUD is inserted into your uterus by your health professional. A plastic string tied to the end of the IUD hangs down through the cervix into the vagina. You can check that the IUD is in place by feeling for this string. The string is also used by a health professional to remove the IUD.

Types of IUDs

• Levonorgestrel (LNg) IUD. The levonorgestrel (LNg) IUD, also known as Mirena, releases levonorgestrel, which is a form of progestin. The LNg IUD appears to be slightly more effective at preventing pregnancy than the copper IUD. Also, unlike other IUDs, it may decrease the risk of pelvic inflammatory disease (PID). The LNg IUD is effective for at least 5 years.
• Copper IUD. The most commonly used IUD is the Nova T. Copper wire is wound around the stem of the T-shaped IUD. The Nova T can stay in place for up to 5 years and is a highly effective form of contraception.

How it works

Both types of IUD prevent fertilization of the egg by damaging or killing sperm. The IUD also affects the uterine lining (where a fertilized egg would implant and grow).

• LNg IUD. This IUD prevents fertilization by damaging or killing sperm and making the mucus in the cervix thick and sticky, so sperm can't get through to the uterus. It also keeps the lining of the uterus (endometrium) from growing very thick.¹ This makes the lining a poor place for a fertilized egg to implant and grow. The hormones in the LNg IUD also relieve irregular menstrual bleeding and cramping.
• Copper IUD. Copper is toxic to sperm. It makes the uterus and fallopian tubes produce fluid that kills sperm. This fluid contains white blood cells, copper ions, enzymes, and prostaglandins.¹

Insertion

You can have an IUD inserted at any time, as long as you are not pregnant. An IUD is inserted into your uterus by your health professional. The insertion procedure takes only a few minutes and can be done in a doctor's office. Sometimes a local anesthetic is injected into the area around the cervix, but this is not always needed.

IUD insertion is easiest in women who have had a vaginal childbirth in the past.

Your health professional may have you feel for the IUD string right after insertion, to be sure you know what it feels like. You may be given antibiotics to prevent infection.

What To Expect After Treatment

You may want to have someone drive you home after the insertion procedure. You may experience some mild cramping and light bleeding (spotting) for 1 or 2 days.

Follow-up

Your health professional may want to see you 4 to 6 weeks after the IUD insertion, to make sure it is in place.

Be sure to check the string of your IUD after every period. To do this, insert a finger into your vagina and feel for the cervix, which is at the top of the vagina and feels harder than the rest of your vagina (some women say it feels like the tip of your nose). You should be able to feel the thin, plastic string coming out of the opening of your cervix. It may coil around the cervix, which can make it difficult to find. Call your health professional if you cannot feel the string or the rigid end of the IUD.

If you cannot feel the string, it doesn't necessarily mean that the IUD has been expelled. Sometimes the string is just difficult to feel or has been pulled up into the cervical canal (which will not harm you). An examination and sometimes an ultrasound will show whether the IUD is still in place. Use another form of birth control until your health professional makes sure that the IUD is still in place.

If you have no problems, check the string after each period and return to your health professional once a year for a checkup.

• The Nova T is approved for use of up to 5 years.
• The LNg IUD is approved for use of up to 5 years.

Why It Is Done

You may be a good candidate for an IUD if you:

• Do not have a pelvic infection at the time of IUD insertion.
• Have only one sex partner who does not have other sex partners and who is infection-free. This means you are not at high risk for sexually transmitted diseases (STDs) or pelvic inflammatory disease (PID), or you and your partner are willing to also use condoms.
• Want an effective, long-acting method of birth control that requires little effort and is easily reversible.
• Cannot or do not want to use birth control pills or other hormonal birth control methods.
• Are breast-feeding.

Copper IUDs are recommended for emergency contraception if you have had unprotected sex in the past few days and need to avoid pregnancy and you plan to continue using the IUD for birth control. As a short-term type of emergency contraception, the copper IUD is more expensive than emergency contraception with hormone pills. The cost is not covered by provincial health plans, including in the case of sexual assault.

How Well It Works

The IUD is a highly effective method of birth control.¹

• When using the LNg IUD, about 1 per 1,000 women becomes pregnant. Over 5 years of use, only about 7 women per 1,000 become pregnant.²
• When using a copper IUD, about 6 per 1,000 women become pregnant. Over 10 years of use, about 20 to 30 women per 1,000 become pregnant.²
• Most pregnancies that occur with IUD use happen because the IUD is pushed out of (expelled from) the uterus unnoticed. IUDs are most likely to come out in the first few months of IUD use, after being inserted just after childbirth, or in women who have not had a baby.

Advantages of IUDs include cost-effectiveness over time, ease of use, lower risk of ectopic pregnancy, and no interruption of foreplay or intercourse.²

Additional advantages of the LNg IUD

In addition, the LNg IUD:

• Reduces heavy menstrual bleeding by an average of 90% after the first few months of use.²
• Improves irregular (spotting and prolonged) menstrual bleeding after 3 to 4 months.²
• Reduces menstrual bleeding and cramps and, in many women, eventually causes menstrual periods to stop altogether. In this case, not menstruating is not harmful.
• May prevent endometrial hyperplasia or endometrial cancer.
• May decrease the risk of pelvic inflammatory disease (PID).
• May effectively relieve endometriosis and is less likely to cause side effects than high-dose progestin.³
• Reduces the risk of ectopic pregnancy.
• Does not cause weight gain.

Risks

Risks of using an intrauterine device (IUD) include:

• Menstrual problems. About 12% of women have a copper IUD removed because of increased menstrual bleeding or cramping.² Women may also experience spotting between periods. However, after about 3 months of increased bleeding or spotting, the LNg IUD reduces menstrual cramps and bleeding by an average of 90%.²
• Perforation. In 1 out of every 1,000 women, the IUD will get stuck in or puncture (perforate) the uterus.¹ Although perforation is rare, it almost always occurs during insertion. The IUD should be removed if the uterus has been perforated.
• Expulsion. About 2% to 10% of IUDs are pushed out (expelled) from the uterus into the vagina during the first year. This usually happens in the first few months of use. Expulsion is more likely when the IUD is inserted right after childbirth or in a woman who has not carried a pregnancy.¹ When an IUD has been expelled, you are no longer protected against pregnancy.

Disadvantages of IUDs include the high cost of insertion, no protection against STDs, and the need to be removed by a health professional.

Disadvantages of the LNg IUD

The LNg IUD may cause non-cancerous (benign) growths called ovarian cysts, which usually go away on their own.

The LNg IUD can cause hormonal side effects similar to those caused by oral contraceptives, such as breast tenderness, mood swings, headaches, and acne. This is rare. When side effects do happen, they usually go away after the first few months.

Pregnancy with an IUD

If you become pregnant with an IUD in place, your health professional may recommend that the IUD be removed. This is because the IUD can cause miscarriage or preterm birth (the IUD will not cause birth defects). Taking out an IUD early in a pregnancy lowers risks of miscarriage or preterm birth. However, IUD removal can also cause a miscarriage. As a pregnancy progresses, miscarriage risk is lower if an IUD is removed than if it is left in place.¹

When to call your health professional

When using an IUD, be aware of warning signs of a more serious problem related to the IUD.

Call your health professional immediately if you have any of the following symptoms. Remember the word "PAINS." Each letter stands for a word associated with a problem:

• Period is late with a copper IUD, or you have abnormal spotting or severe bleeding.
• Abdominal pain, severe cramping, or abdominal pain with sexual intercourse
• Infection with or exposure to a sexually transmitted disease (STD) or symptoms of a vaginal infection, such as abnormal vaginal discharge
• Not feeling well or having a fever of 38°C (100.4°F) or higher
• Strings from IUD are missing or are longer or shorter than normal

Call your health professional to schedule an appointment if you:

• Cannot feel the strings of your IUD. (Use condoms as backup birth control until your health professional has checked your IUD.)
• Have severe or prolonged vaginal bleeding.
• Miss a menstrual period, unless you have the LNg IUD. It is normal to miss a period or stop menstruating while you are using the LNg IUD, and this is not a cause for concern.

What To Think About

The IUD is most likely to work well for women who have been pregnant before. Women who have never been pregnant are more likely to expel the IUD or have more pain and cramping after insertion. However, they can still use the IUD.¹

Pelvic inflammatory disease (PID) concerns have been linked to the IUD for years. However, it is now known that the IUD itself does not cause PID. Instead, if you have a genital infection when an IUD is inserted, the infection can be carried into your uterus and fallopian tubes. If you are at risk for a sexually transmitted disease (STD), your health professional will test you and treat you if necessary, before you get an IUD.

Intrauterine devices reduce the risk of all pregnancies, including ectopic (tubal) pregnancy. However, if a pregnancy does occur while an IUD is in place, it is a little more likely that the pregnancy will be ectopic. Ectopic pregnancies require medication or surgery to remove the pregnancy. Sometimes the fallopian tube on that side must be removed as well.

IUD use and medical conditions

An IUD can be a safe birth control choice for women who:⁴

• Have a history of ectopic pregnancy. Both the copper IUD and LNg IUD are appropriate.
• Have a history of irregular menstrual bleeding and pain. The LNg IUD may be appropriate for these women and women who have a bleeding disorder or those who take blood thinners (anticoagulants).
• Have a risk for bacterial endocarditis. Antibiotics would be used at the time of insertion and removal to prevent infection.
• Have diabetes.
• Are breast-feeding.
• Have a history of endometriosis. The LNg IUD is a good choice for women who have endometriosis.

Considerations

IUDs may not be a good choice if you:

• Have never been pregnant (you are more likely to have pain with an IUD and are more likely to have the IUD come out after it is inserted).
• Have a sexually transmitted disease (STD) currently or had one within the past 3 months.
• Are not willing to use condoms to protect yourself from sexually transmitted diseases.
• Have an active infection of your vagina or cervix.
• Have pelvic inflammatory disease (PID) or have a recent history of PID.
• Have a bleeding disorder or take blood-thinners (anticoagulants). Although you cannot use the copper IUD, you can use the LNg IUD.
• Have a history of problems with IUDs.
• Have abnormalities of your uterus.
• Have a uterine infection after childbirth or a septic abortion.
• Have uterine bleeding of unknown origin.
• Have an allergy to copper, so the Nova T or Gyne-T 380 would not be an option.

If you have one of the older, all-plastic IUDs, such as the Lippes Loop, ask your health professional at your next checkup about replacing this IUD with a more effective copper or hormonal one.

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Author:	Merrill Hayden Carrie Henley	Last Updated: August 16, 2006
Medical Review:	Adam Husney, MD - Family Medicine Joy Melnikow, MD, MPH - Family Medicine Kirtly Jones, MD - Obstetrics and Gynecology Femi Olatunbosun, MB, FRCSC - Obstetrics, Gynecology and Reproductive Medicine
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