Female Contraception

Description

Alternative Names

Intrauterine Devices (IUDs)

The intrauterine device (IUD) is a small plastic 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. Precisely how the IUD prevents pregnancy is a mystery. Some experts believe that the presence of the IUD alters the fluids in the fallopian tubes and uterus, which reduces the chances for fertilization.

The intrauterine device shown uses copper as the active contraceptive, others use progesterone in a plastic device. IUDs are very effective at preventing pregnancy (less than 2% chance per year for the progesterone IUD, less than 1% chance per year for the copper IUD). 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.

IUD Forms

The two standard IUDs are copper-releasing or progestin-releasing IUDs. Both are effective and have specific advantages and disadvantages:

Copper-Releasing IUDs. Copper-releasing IUDs (ParaGard, Nova T) are partly wrapped in copper and can remain in the uterus for 10 years. So-called frameless copper IUDs (Gynefix, FlexiGard, or CuFix) consist of nylon thread that holds the copper sleeves. They are equal to standard copper IUDs in effectiveness and may have fewer side effects. They are difficult to implant and not yet available in the US. A number of other new designs are also under investigation.

Progestin-Releasing IUDs.These IUDs continuously release progestin into the uterus in small amounts. They may be specifically beneficial for women with menstrual disorders. The levonorgestrel-releasing intrauterine system, or LNG-IUS (Mirena), releases progestin for up to five years. To date, of all the IUDs, the LNG-IUS appears to solve more problems than the other versions. It is long acting, safe, is very effective in preventing heavy bleeding, and helps reduce cramps. In fact, one expert described the LNG-IUS as a nearly ideal contraceptive.With short-term IUDs (Progesterone T, Progestatsert) the progestin supply runs out after a year and a new IUD must be inserted.

FibroPlant is a unique "frameless" LNG-IUS device that is very small and secretes a very low dose of progestin. It appears to have very few hormonal effects, although comparison studies are needed to prove any significant advantages over the Mirena.

Inserting the IUD

With some exceptions, an IUD can be inserted at any time, except during pregnancy. 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 user should also check for the strings after each period.)
• They are used for pulling the IUD out of the uterus when removal is warranted.

Candidacy for the IUD

The IUD is often an excellent choice for women who do not anticipate future pregnancies, but who do not wish to be sterilized. Women who are unable to use hormonal contraceptives (for example, those with heart disease, epilepsy, migraines, hypertension, or liver disease) may be good candidates for the copper IUD.

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. Other women who may be poor candidates for the IUD are those with the following history or conditions:

• Current or recent history of pelvic infection.
• Risk factors for sexually transmitted diseases (such as having multiple sexual partners).
• History of menstrual disorders. (Progestin-releasing IUDs may be an option for women with heavy or painful bleeding. They should avoid the copper-releasing IUDs, however.)
• Current pregnancy.
• Abnormal Pap tests.
• Cervical or uterine cancer.
• Anatomical abnormalities of the uterus.
• A very large or very small uterus.

Advantages of the Intrauterine Device

The 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 1% of American women 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. [See Infection below.] In fact, increasing its use would most likely reduce both the number of abortions and sterilizations in the US, without producing unwanted infertility.

IUDs in general have the following advantages:

• The IUD is more effective than OCs 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.

There also additional advantages, depending on the specific IUD:

• The progestin-releasing LNG-IUS (Mirena) is now considered to be one of the best options for treating menorrhagia (heavy menstrual bleeding). Some studies suggest it might help avoid hysterectomy in 80% of cases. Note: irregular break-through bleeding can occur for the first six 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.

Disadvantages and Complications of Specific Intrauterine Devices

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 a day or two after insertion, and others may suffer cramps and backaches for weeks or months. Over-the-counter painkillers can usually moderate this discomfort.

Menstrual Bleeding with the Copper T IUD. Both 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, particularly with the LNG-IUS is a major advantage for women who suffer from heavy menstrual bleeding but may be perceived as a problem for others.)

Menstrual difficulties can be so troublesome with either IUD that, according to one study, they were responsible for a removal rate of 5% to 15% within a year of insertion.

Infection. The current versions of IUD pose a slightly higher risk for pelvic inflammatory disease in the first month following insertion. The risk of PID in women without any symptoms of sexually transmitted infections, however, is the same in both IUD users and nonusers. Some physicians employ preventive antibiotics before inserting the IUD, but a major analysis did not find that this was helpful. (An early IUD, the Dalkon Shield, which sported a braided tail, was banned after reports of several deaths and a very high rate of infection.)

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

Expulsion. An estimated 2% to 8% of IUDs are expelled from the uterus within the first year. Expulsion is most likely to occur during the first three months after insertion. Expulsion rates may be higher than average if the IUD is inserted immediately after delivery of a child. In one out of five cases, the user 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 users are strongly advised to examine their sanitary napkins for the IUD every day during the period and to regularly check for the IUD strings throughout the month.

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.

Click the icon to see an image of an ectopic pregnancy.

If the IUD is removed right after conception, than 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 inserter.