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Intrauterine Devices (IUDs)

by Laura Sech, Penina Segall-Gutierrez, MD, MSc; Emily Silverstein; Daniel R. Mishell, Jr., MD

In the US, 5.5% of women use intrauterine devices (IUDs); IUDs are becoming more popular because of their advantages over oral contraceptives:

  • IUDs are highly effective.

  • IUDs have minimal systemic effects.

  • Only one contraceptive decision every 3, 5, or 10 yr is required.

In the US, 3 IUDs are currently available. There are 2 types of levonorgestrel-releasing IUDs; one is effective for 3 yr and has a 3-yr cumulative pregnancy rate of 0.9%. The other is effective for 5 yr and has a cumulative 5- yr pregnancy rate of 0.5%. The 3rd IUD is a copper-bearing T380A IUD. It is effective for 10yr; it has a cumulative 12-yr pregnancy rate of < 2% (see Table: Comparison of Intrauterine Devices).

Comparison of Intrauterine Devices

Feature

Levonorgestrel

Copper-T380A

3-yr IUD

5-yr IUD

Efficacy (1st-yr pregnancy rate with typical use)

0.3–0.5%

0.2%

0.8%

Reversibility

Rapid

Rapid

Rapid

Maximum duration

3 yr

5 yr

10 yr

Changes in bleeding

Irregular bleeding

Amenorrhea at 1 yr: 6%

Irregular bleeding

Amenorrhea at 1 yr: 20%

No change in cyclical nature of cycles

Mean monthly blood loss

5 mL

50‒80 mL

Additional benefits

May be used to treat heavy menstrual bleeding, chronic pelvic pain, or endometriosis

May be used as emergency contraception

Nonhormonal

Adverse effects

Minimal: Headache, spotting, breast tenderness, nausea (which usually resolves within 6 mo)

Same as for 3-yr IUD

More severe menstrual cramps (usually relieved by NSAIDs) and heavier flow

Primary mechanism of action

Thickens cervical mucus and prevents fertilization

Same as for 3-yr IUD

Use of copper ions to produce a sterile inflammatory response that is toxic to sperm, thus preventing fertilization

Clinicians do not need to do a Papanicolaou (Pap) test before they insert an IUD unless they suspect cervical lesions are present. Then, a Pap test or cervical biopsy should be done. Also, clinicians do not need to wait for results of STD testing (for gonorrhea and chlamydial infection) before they insert an IUD. However, STD testing should be done just before the IUD is inserted, and if results are positive, patients should be treated with appropriate antibiotics; the IUD is left in place. If purulent discharge is observed at the time of IUD insertion, the IUD is not inserted, STD testing is done, and empiric treatment with antibiotics is started before test results are available.

When IUDs are inserted, sterile technique is used as much as possible. Bimanual examination should be done to determine the position of the uterus, and a tenaculum should be placed on the anterior lip of the cervix to stabilize the uterus, straighten the uterine axis, and help ensure correct placement of the IUD. A uterine sound device or an endometrial aspirator (used for biopsy) is often used to measure the length of the uterine cavity before IUD insertion. The package insert for the IUD should be reviewed before insertion because the 3 types of IUDs are inserted differently.

Most women can use an IUD. Contraindications include the following:

  • Current pelvic infection, usually pelvic inflammatory disease (PID), mucopurulent cervicitis with a suspected STD, pelvic TB, septic abortion, or puerperal endometritis or sepsis within the past 3 mo

  • Anatomic abnormalities that distort the uterine cavity

  • Gestational trophoblastic disease with persistently elevated serum β–human chorionic gonadotropin (β-hCG) levels (a relative contraindication because supporting data are lacking)

  • Unexplained vaginal bleeding

  • Known cervical or endometrial cancer

  • Pregnancy

  • For levonorgestrel-releasing IUDs, breast cancer or allergy to levonorgestrel

  • For copper-bearing T380 IUDs, Wilson disease or allergy to copper

Conditions that do not contraindicate IUDs include the following:

  • Religious beliefs that prohibit abortion because IUDs are not abortifacients (however, a copper IUD used for emergency contraception may prevent implantation of the blastocyst)

  • A history of PID, STDs, or ectopic pregnancy

  • Contraindications to contraceptives that contain estrogen (eg, history of venous thromboembolism, smoking > 15 cigarettes/day in women > 35, migraine with aura, migraine of any type in women > 35)

  • Breastfeeding

  • Adolescence

Vaginal bleeding stops completely within 1 yr in 6% of women using the 3-yr IUD and in 20% of women using the 5-yr IUD. A copper-bearing T380A IUD may cause heavier menstrual bleeding and more severe cramping, which can be relieved by NSAIDs (eg, ibuprofen). Women should be told about these effects before the IUD is inserted because this information may help them decide which type of IUD to choose.

An IUD may be inserted at any time during the menstrual cycle if a woman has not had unprotected intercourse during the past month.

If a woman has had unprotected intercourse within the past 7 days, a copper-bearing T380 IUD may be inserted as emergency contraception. The copper-bearing IUD may be left in place for long-term contraception if the woman desires. The resumption of menses plus a negative pregnancy test reliably excludes pregnancy; a pregnancy test should be done 2 to 3 wk after insertion to be sure that an unintended pregnancy has not occurred before insertion.

An IUD may be inserted immediately after an induced or a spontaneous abortion during the 1st or 2nd trimester and immediately after delivery of the placenta during a cesarean or vaginal delivery.

IUDs do not increase and may decrease the risk of uterine cancer.

Complications

Average IUD expulsion rates are usually < 5% within the first year after insertion; however, expulsion rates are higher if the IUD is inserted immediately (< 10 min) after a delivery. After insertion, a clinician confirms correct placement at 6 wk by looking for the strings attached to the IUD, which are typically trimmed to 3 cm from the external cervical os.

The uterus is perforated in about 1/1000 IUD insertions. Perforation occurs at the time of IUD insertion. Sometimes only the distal part of the IUD penetrates; then over the next few months, uterine contractions force the IUD into the peritoneal cavity. If the string is not visible during pelvic examination, the uterine cavity is probed with a sound or biopsy instrument (unless pregnancy is suspected) and/or ultrasonography is done. If the IUD is not seen, an abdominal x-ray is taken to exclude an intraperitoneal location. Intraperitoneal IUDs may cause intestinal adhesions. IUDs that have perforated the uterus are removed via laparoscopy.

If expulsion or perforation is suspected, a backup contraceptive method should be used.

Rarely, salpingitis (pelvic inflammatory disease) develops during the first month after insertion because bacteria are displaced into the uterine cavity during insertion; however, this risk is low and routine antibiotic prophylaxis is not indicated. If PID develops, antibiotics should be given. The IUD need not be removed unless the infection persists despite antibiotics. IUD strings do not provide access for bacteria. Except during the first month after insertion, IUDs do not increase the risk of pelvic inflammatory disease.

The incidence of ectopic pregnancy is much lower in IUD users than in women using no contraceptive method because IUDs effectively prevent pregnancy. However, if a women becomes pregnant while an IUD is in place, she should be told that risk of ectopic pregnancy is increased, and she should be evaluated promptly (see Ectopic Pregnancy).

Key Points

  • IUDs are highly effective, have minimal systemic effects, and involve only one contraceptive decision every 3, 5, or 10 yr depending on the IUD chosen.

  • Types include levonorgestrel-releasing IUDs (effective for 3 yr or 5 yr, depending on the type) and a copper-bearing IUD (effective for 10 to 12 yr).

  • A Pap test is not required before IUD insertion.

  • Inform women that both types of IUDs can affect menstrual bleeding (amenorrhea within 1 yr in 6% of women using the 3-yr IUD and in 20% of those using the 5-yr IUD and possibly heavier menstrual bleeding and more severe cramping in women using the copper-bearing T380 IUD).

  • Confirm correct placement of the IUD by checking the strings 6 wk after insertion.

  • If the strings are not visible during the pelvic examination, probe the uterine cavity using a uterine sound or biopsy instrument (unless pregnancy is suspected), and if needed, do ultrasonography or take an abdominal x-ray to check for an intraperitoneal location.

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Drugs Mentioned In This Article

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  • ADVIL, MOTRIN IB
  • MIRENA, PLAN B

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