Intrauterine devices (IUDs) are small flexible devices made of metal and/or plastic that prevent pregnancy when inserted into a woman’s uterus through her vagina.
Nearly 15% of women of reproductive age (approximately 160 million women) currently use IUD’s. Much of their popularity stems from their effectiveness combined with their long duration. The most widely used IUD’s are copper-bearing IUDs.
Inert (unmedicated) and progestin-releasing IUD’s (levonorgestrel or progesterone) are less widely available. IUD’s are a safe and effective method of reversible, long-term contraception for most women. They do not affect breastfeeding, interfere with intercourse, or have hormonal side effects; only some gynecologic and obstetric conditions and infections preclude use of the method.
One drawback of IUD’s is their tendency to cause heavy menstrual bleeding. Unless otherwise stated, the following information applies to copper IUD’s.
Characteristics Of Intrauterine Devices
|Effectiveness||Age Limitations||Parity Limitations||Mode of Action|
|0.4% to 2.5% failure rate for copper IUDs and 0.1% failure rate for the levonorgestrel-IUD during the first year of typical use.||No restrictions on use for women age 20 and over||No restrictions on use for parous women; nulliparous women can generally use IUDs if they do not have a history of pelvic infection, a previous ectopic pregnancy, or multiple sex partners (or partner who has other partners)||Through a combination of mechanisms: inhibiting sperm migration in the upper female genital tract, inhibiting ovum transport, and stimulating endometrial changes|
|Effect on STI risk||Drug Interaction||Duration of Use||Return to Fertility|
|Not Protective||None||The Copper T 380A device remains effective for up to 10 years; the Multi-load copper IUD remains effective for up to five years; the levonorgestrel-releasing IUD is effective for at least five years. Most women can use IUDs safely throughout their reproductive years (if the woman is satisfied with the method and has no problems with it)||Immediately upon removal|