Intrauterine devices (IUDs) are the third most common birth control method used by American women (behind tubal ligation and the oral contraceptive pill), and their use has been growing steadily.
An IUD is a type of long-acting, reversible contraception (LARC) that provides birth control for three to 10 years, depending on the type. A small, flexible, T-shaped device, an IUD is inserted into the uterus through the vagina. Generally speaking, IUDs prevent pregnancy by reducing the ability of sperm to reach the egg for fertilization.
Research shows that 80% of women who use IUDs are satisfied with the method. By comparison, only 54% of women who use oral contraceptive pills report being satisfied with that form of birth control.
Although IUDs are one of the most effective forms of birth control, they are still not used as much as other contraceptive methods. Part of the reason may have to do with the various choices women have regarding types of IUDs.
Below, Tessa Madden, MD, a Yale Medicine obstetrician-gynecologist and family planning specialist, talks more about IUDs and answers many of the common questions women have about them.
What are the different types of IUDs, and how do they work?
Whereas some types of birth control, such as the pill, prevent pregnancy by stopping ovulation, IUDs work differently—and vary by type. There are two kinds of IUDs: hormonal and copper.
Hormonal IUDs release progestin, a synthetic version of the hormone progesterone. The hormone causes the cervical mucus to thicken, which prevents the sperm from getting into the uterus and reaching an egg.
Copper IUDs do not contain hormones; instead, they have a small amount of copper, which causes an immune response in the uterus, creating a toxic environment for sperm.
How long do IUDs last?
A hormonal IUD can remain in place for up to eight years, depending on the brand. The four brands currently available in the United States are Mirena® (approved for up to eight years), Liletta® (up to eight years), Kyleena® (up to five years), and Skyla® (up to three years).
The copper IUD, sold under the brand name Paragard®, is approved for up to 10 years. At the expiration date, a woman can have the IUD removed and replaced with a new one.
It's important to know that your doctor can remove an IUD at any time, and you can get pregnant as soon as it is taken out.
How do IUDs affect your period?
With hormonal IUDs, the amount of bleeding can vary by IUD type. Standard-dose IUDs are more likely to cause the period to stop; lower-dose IUDs are more likely to cause lighter monthly bleeding.
Women who use copper IUDs typically have a monthly period. Sometimes, the period can be heavier, longer, or crampier than usual, especially during the first few months of use. This improves over time for most women.
How do you decide which IUD is right for you?
When helping a woman decide which kind of IUD is right for her, Dr. Madden says she first asks if they would prefer to have a regular period, a lighter period, or no period at all.
“It’s important to discuss this because some women prefer to have their period every month,” Dr. Madden explains. “I also ask them what their period is like right now. If a woman already has a very heavy period and doesn’t like that, then a copper IUD might not be her first choice as it could make her period heavier.”
Another deciding point for women is the length of time it remains effective. “If a woman is done with childbearing, she might be interested in one that lasts longer,” Dr. Madden says.
Does IUD insertion hurt?
It depends. An IUD, which is inserted by a doctor or other health care provider during an office visit, can be done at any time during a woman’s menstrual cycle. The provider inserts a speculum into the vagina and uses a small tube to pass the IUD through the cervical opening and into the uterus.
“It will only take a few minutes, which is important for women to know because a few minutes of discomfort is a lot different than 15 minutes or half an hour,” Dr. Madden says. “But when the IUD is placed through the cervix, most women will experience cramping.”
The discomfort is highly variable, she adds. “For example, a woman who has not been pregnant before may be more likely to have cramps afterward, because her uterus is smaller and the IUD may cause some uterine irritability when inserted. Also, patients who experience cramping with their periods may have more intense cramping during the procedure and afterward,” she says. “However, I have had many patients tell me they’re fine after the insertion is over, and they experience very little cramping afterward.”
For some women, cramps may continue one to two days after insertion. To help with potential cramping pain, Dr. Madden recommends that most patients take ibuprofen before and after insertion. Or, if the IUD insertion is expected to be more difficult—as it can be for a woman who has not yet had children or has had previous cervix procedures—a local anesthetic may be used to numb the area. If you are worried about pain with insertion, Dr. Madden recommends talking to your provider.
Following the insertion of a hormonal IUD, most women have some irregular bleeding, which is typically light, for the first three to six months. For a copper IUD, there may be some spotting after insertion or for the first couple of months, Dr. Madden adds.
Follow-up visits are not necessary after insertion, unless a woman experiences pain (beyond cramping), heavy bleeding, abnormal vaginal discharge, fever, or if the IUD is expelled.
What is it like to have an IUD removed?
A woman can decide to have her IUD removed at any time. The device has strings that extend into the vagina, allowing a medical provider to remove it using a special instrument.
“IUD removal is not as uncomfortable as having it inserted. Usually, women just have one big cramp as it’s removed, and there isn’t any cramping afterward,” Dr. Madden says. “If the strings are not visible, which is infrequent—about 2% of the time—then sometimes we use a special instrument to retrieve the IUD.”
In this case, the removal may feel similar to the initial IUD insertion, she adds.
How effective are IUDs, and how quickly do they start working?
IUDs are one of the most effective forms of reversible contraception, with a typical one-year failure rate of less than 1%.
Hormonal IUDs start to work within seven days of insertion; copper IUDs work immediately after insertion.
“Both types of IUDs can be used as emergency contraception up to five days after unprotected intercourse,” says Dr. Madden. “However, if you are already pregnant, an IUD will not work as emergency contraception.”
It’s important to know that pregnancy with an IUD in place carries increased risks, so be sure to talk to your health care provider if you are concerned, she adds.
What are the side effects and risks of an IUD?
The most common reasons for IUD removal are irregular bleeding and cramping.
Hormonal IUDs can cause irregular bleeding during the first several months after insertion. Some women will stop having periods altogether—the likelihood of this depends on the type. Many women will have light and/or infrequent bleeding.
Copper IUDs may increase the amount of menstrual bleeding and cramping. Both IUD types can cause cramping post-insertion. Hormonal IUDs typically have less bleeding and, thus, tend to have less cramping over time.
Serious risks from IUDs are rare, but possible. One type of complication is IUD expulsion, which means the device comes out of the uterus by accident; if this happens, a medical provider will need to replace the device. An expulsion is not dangerous, but the IUD won’t prevent pregnancy if it is not in the correct location.
Another potential complication of IUDs is uterine perforation, where the IUD moves through the uterine wall. In this case, surgical removal is required.
There is less than a 1% risk of infection within the first three to six months following insertion. If an infection occurs, it can be treated with antibiotics.
Can an IUD be removed if you want to get pregnant?
If a woman decides to become pregnant, she can have the IUD removed. “I usually tell a patient to wait until they have one normal period before trying to conceive to allow for normal endometrium to develop prior to implantation,” notes Dr. Madden.
Do IUDs affect your cancer risk?
All types of IUDs may reduce the risk of uterine and ovarian cancer. A recent study showed a small increase in the risk of breast cancer among women who use or recently used combined oral or progestin-only contraceptives. (The overall risk of a woman in the U.S. developing breast cancer at some point in her life is about 13%, according to the American Cancer Society.) It is unclear if the increased risk applies to hormonal IUDs.
Dr. Madden notes that the data regarding IUDs and breast cancer risk is not conclusive. “There is conflicting data out there. Even if a woman has a family history of breast cancer, it doesn’t always mean she can’t have an IUD. But we like to discuss the risks with our patients, because we believe they should be educated,” she says.
However, women with breast cancer should not get a hormonal IUD, and those with cervical and/or uterine cancer may not be candidates for any type of IUD, she adds.
What else should women know about IUDs?
Most women can safely use IUDs, but there are some instances in which side effects or complications may be more likely—for example, for women with current sexually transmitted infections (STIs) or pelvic infections, or those who may be pregnant.
Also, women with a copper allergy or Wilson disease (a disease where copper accumulates in the liver) should not get a copper IUD.
Although uncommon, the size or shape of a woman’s uterus may make it difficult to place an IUD correctly, adds Dr. Madden.
It’s also important to note that IUDs do not protect against STIs.