Intrauterine Devices (IUDs):

The intrauterine device (IUD) is a small plastic T-shaped device that is inserted into the uterus. An IUD's contraceptive action begins as soon as the device is placed in the uterus and stops as soon as it is removed. IUDs have an effectiveness rate of close to 100%. They are also a reversible form of contraception. Once the device is removed, a woman regains her fertility.

The intrauterine device (IUD) is one of the safest, least expensive, and most effective contraceptive devices available. In spite of its clear advantages and current safety record, only 2% of American women who practice contraception currently use the IUD. (Over 10% of European women have chosen the IUD.) This low use in America is mainly due to persisting and now unwarranted fears of serious infection and other complications. However, the evidence available today should reassure providers and patients about the following concerns:

• Pelvic infections. What was thought to be an increased risk of pelvic inflammatory disease has proven not to be true. Large groups of patients have been evaluated, and their risk does not seem to be any greater than the risk in the general population The risk for infection may be increased around the time of insertion of the IUD, but routine screening before insertion is generally not recommended There is also no evidence that IUD usage increases the risk of HIV infection.
• Infertility. IUDs were thought to cause infertility, mostly because of concerns about infections. However, studies have shown that women with a history of using an IUD are no more likely to be diagnosed with infertility than those who have not used IUDs. This seems to be true for women who have never been pregnant or women who have been pregnant previously.
• Ectopic pregnancy. Another concern was a presumed increased risk for an ectopic pregnancy. In reality, women using IUDs have a significantly lower rate of ectopic pregnancies than women using no contraception at all. Even for women who have a history of ectopic pregnancies when not using contraception, the IUD is considered safe and may even lower their risk for another one.

The intrauterine device (IUD) shown uses copper as the active contraceptive. Others use progesterone in a plastic device. IUDs are very effective at preventing pregnancy (less than 1% chance per year). IUDs come with increased risk of ectopic pregnancy and perforation of the uterus and do not protect against sexually transmitted disease. IUDs are prescribed and placed by health care providers.

Intrauterine Device Forms

Two types of intrauterine devices (IUDs) are available in the United States:

• Copper-Releasing (ParaGard). This type of IUD can remain in the uterus for up to 10 years. Copper ions released by the IUD are toxic to sperm, thus preventing fertilization.
• Progestin-Releasing (Mirena). This type of IUD can remain in the uterus for up to 5 years. Mirena is also known as a levonorgestrel-releasing intrauterine system, or LNG-IUS. Levonorgestrel impairs sperm motility and viability, thus preventing fertilization. LNG-IUS is long-acting, safe, very effective in preventing heavy bleeding, and helps reduce cramps. In fact, some doctors describe it as a nearly ideal contraceptive. It is also helpful for women with menstrual disorders, particularly heavy bleeding.

Inserting an Intrauterine Device

With some exceptions, an intrauterine device (IUD) can be inserted at any time, except during pregnancy or when an infection is present. It may be inserted immediately postpartum or after elective or spontaneous miscarriage. It is typically inserted in the following manner by a trained health professional:

• A plastic tube containing the IUD (the inserter) is slid through the cervical canal into the uterus.
• A plunger in the tube pushes the IUD into the uterus.
• Attached to the base of the IUD are two thin but strong plastic strings. After the instruments are removed, the health care provider cuts the strings so that about an inch of each dangles outside the cervix within the vagina.

The strings have two purposes:

• They enable the user or health care provider to check that the IUD is properly positioned. (Because the IUD has a higher rate of expulsion during menstruation, the woman should also check for the strings after each period, especially if she has heavy cramps.)
• They are used for pulling the IUD out of the uterus when removal is warranted.

The insertion procedure can be painful and sometimes causes cramps, but for many women it is painless or only slightly uncomfortable. Patients are often advised to take an over-the-counter painkiller ahead of time. They can also ask for a local anesthetic to be applied to the cervix if they are sensitive to pain in that area. Occasionally a woman will feel dizzy or light-headed during insertion. Some women may have cramps and backaches for 1 - 2 days after insertion, and others may suffer cramps and backaches for weeks or months. Over-the-counter painkillers can usually moderate this discomfort.

Candidates for the Intrauterine Device

Intrauterine devices are an excellent choice of contraception for women who are seeking a long-term and effective birth control method, particularly those wishing to avoid risks and side effects of contraceptive hormones. The LNG-IUS may be better suited for women with heavy or regular menstrual flow.

Around the time of insertion and shortly afterwards, women should be considered at low risk for sexually transmitted disease (mutually monogamous relationship, using condoms, or not sexually active).

Women with risk factors that preclude hormonal contraceptives should probably avoid progestin-releasing IUDs, although the progestin doses are much lower with LNG-IUS and probably do not pose the same risks.

Women with the following history or conditions may be poor candidates for IUDs:

• Current or recent history of pelvic infection
• History of menstrual disorders -- mostly for the copper-releasing IUDs, however
• Current pregnancy
• Abnormal Pap tests
• Cervical or uterine cancer
• A very large or very small uterus

IUDs have the following advantages:

• The IUD is more effective than oral contraceptives at preventing pregnancy, and it is reversible. Once it is removed, fertility returns. (In spite of outdated concerns, studies have found no adverse effects on fertility with the current IUDs.)
• Unlike the pill, there is no daily routine to follow.
• Unlike the barrier methods (spermicides, diaphragm, cervical cap, and the male or female condom), there is no insertion procedure to cope with before or during sex.
• Intercourse can resume at any time, and, as long as the IUD is properly positioned, neither the user nor her partner typically feels the IUD or its strings during sexual activity.
• It is the least expensive form of contraception over the long term.

Additional advantages, depending on the specific IUD, include:

• The progestin-releasing LNG-IUS (Mirena) is now considered to be one of the best options for treating menorrhagia (heavy menstrual bleeding). (However, irregular breakthrough bleeding can occur during the first 6 months.) It may even be appropriate and protective for women with uterine fibroids.
• The copper-releasing IUDs do not have hormonal side effects and may help protect against endometrial (uterine) cancer.

Complications of Specific Intrauterine Devices

Menstrual Bleeding. Both intrauterine device (IUD) forms have effects on menstruation, although they differ significantly by type:

• Copper releasing IUDs can cause cramps, longer and heavier menstrual periods, and spotting between periods. Prescription medications are available to control the bleeding and pain, which, in any event, usually subside after a few months.
• Progestin-releasing IUDs produce irregular bleeding and spotting during the first few months. Bleeding may disappear altogether. (This characteristic is a major advantage for women who suffer from heavy menstrual bleeding but may be perceived as a problem for others.)

Ovarian Cysts. The LNG-IUS may increase the risk for benign ovarian cysts, but such cysts usually do not cause symptoms and resolve on their own.

Expulsion. An estimated 2 - 8% of IUDs are expelled from the uterus within the first year. Expulsion is most likely to occur during the first 3 months after insertion. Expulsion rates may be higher than average if the IUD is inserted immediately after delivery of a child. In 1 in 5 cases, the woman fails to notice that the device is gone, and thus faces the risk of unintended pregnancy. The risk for expulsion is highest during menstruation, so women should be sure to check the strings to make sure the IUD is in place.

Effects on Pregnancy. None of the current IUDs increase the risk for infertility. In the very unlikely event that a woman conceives with an IUD in place, however, there is a higher risk of an ectopic pregnancy or miscarriage.

If the IUD is removed right after conception, the risk for miscarriage is close to average (about 20%). There is no evidence that the IUD in a pregnant woman increases the risk for birth defects in the infant.

Perforation. A potentially serious complication of the IUD is the accidental perforation of the uterus during insertion or later perforation if the IUD shifts position. Such an occurrence is very rare, and the risk is higher or lower depending on the skill of the doctor.