June 20, 2011 -- Intrauterine devices (IUDs) and implantable contraceptives may not be popular, but they are among the most reliable contraceptive methods available.
"IUDs and implants should be considered first-line contraceptives for a majority of women," says Eve Espey, MD, MPH, an associate professor of obstetrics and gynecology at the University of New Mexico in Albuquerque. She co-authored a paper on these choices in the American Congress of Obstetricians and Gynecologists' Practice Bulletin.
Still, these methods have never really caught on among women for several reasons, including concern about side effects such as pelvic infections. Fewer than 6% of women in the U.S. used IUDs between 2006 and 2008.
As it stands, condoms and oral contraceptives are most commonly used methods of birth control. "We should be recommending IUDs and contraceptive implants because they are so much more effective at preventing unintended pregnancy than condoms and pills," Espey says.
The majority of unintended pregnancies among contraceptive users occur because of inconsistent or incorrect contraceptive use, and this is where implants and IUDs stand out from the pack. They are maintenance-free, which means there is virtually no margin of error, she says.
Maintenance-Free Birth Control?
There are two IUDs available in the U.S. Both are small, T-shaped devices made of flexible plastic that are inserted into the uterus during a routine doctor's visit. ParaGard IUD contains copper and is effective for 10 years. Mirena contains a small amount of the hormone progestin and is effective for five years. Both devices prevent a fertilized egg from attaching to the uterine wall. The copper IUD also interferes with the sperm's ability to move through the uterus and into the fallopian tubes.
"These both have a tremendous safety record and well-known acceptability by patients," she says. Espey says she checks the copper IUD after five to 10 years.
"If Mirena fails, you will go back to regular, heavy menstrual period, so it may be obvious," she says.
Implanon is a single-rod contraceptive implant that inserted under the skin of the upper arm that releases the hormone progestin over a three year period. "You can feel it, so I don't recommend a lot in the way of checking," she says.
Matching Women With the Right Birth Control
Steven Goldstein, MD, a professor of obstetrics and gynecology at New York University Langone Medical Center in New York City, agrees that IUDs are underused.
The over-arching issue is one of compliance, he says. "IUDs and implantable contraceptives are most effective because they have no aspect of patient compliance, but when birth control pills are used properly, they are more effective than IUDs."
"IUDs have gotten bad rap and they don't deserve it, and for the right women at the right time, they are a godsend," he says.
In the 1980s, an IUD called the Dalkon Shield was linked to increased risk for pelvic infections in some women. The company was ultimately forced out of business due to lawsuits. As a result, many women may still have lingering concerns over IUD safety.
"I recommend IUDs to women in stable monogamous relationships who have had a child already," Goldstein says. IUDs are still effective in women who have not had children, but they are easier to insert in women whose uterus has expanded as a result of a previous pregnancy.
Monogamy is important if you are considering an IUD, he says. "If you catch an STD, the IUD can serve as wick to help spread it and can end up with a severe pelvic infection and infertility," he says. (Condoms will also reduce the risk of developing an STD).
"It is about matching the right women with the right contraceptive method," he says. "We need to individualize the contraceptive benefits and non-contraceptive benefits and risks to the patient. It's not one-size-fits-all."