The intrauterine device (IUD) is a T-shaped piece of plastic about the size of a quarter that is placed inside the uterus to prevent pregnancy. Two types of IUDs are available — one is covered with copper, the other releases the hormone progesterone. There are two different brands of progesterone IUD available in the United States.
How Does It Work?
The copper-coated IUD primarily prevents pregnancy by not allowing the sperm to fertilize the egg. It may also make it harder for a fertilized egg to implant in the uterus. When an IUD is coated with progesterone, it works in a similar way, but also thickens the cervical mucus, thins the uterine lining, and in some cases stops altogether. This prevents sperm from fertilizing an egg and implanting.
One type of progesterone IUD also can be used to help reduce blood flow for girls who have heavy, painful periods (sometimes called dysmenorrhea).
How Well Does It Work?
Both types of IUDs are very effective at preventing pregnancy. Over the course of a year, fewer than 1 out of 100 typical couples using an IUD will have an accidental pregnancy.
The IUD is effective from the time it is put in, and it lasts a long time. A copper IUD can stay in place for up to 10 years. Progesterone IUDs can stay in place for 3 to 5 years, depending on the brand. This makes the IUD a good option for women who are not ready to start a family. Even though an IUD can stay in place for a long time, a gynecologist or specialized nurse practitioner can remove it at any time.
The IUD does not protect against sexually transmitted diseases (STDs). People who are having sex must always use condoms along with the IUD to protect against STDs.
A doctor or nurse practitioner will check to be sure a girl doesn't have any STDs before putting in an IUD. If a girl gets an IUD put in at the same time she has an infection, it could lead to pelvic inflammatory disease (PID).
Abstinence (not having sex) is the only method that always prevents pregnancy and STDs.
Possible Side Effects
The most common side effects of the IUD include:
irregular bleeding for the first few months
with the copper IUD, heavier periods with more cramps
lighter and shorter periods (or no periods) with some kinds of progesterone IUDs
PMS-like symptoms, such as headaches, acne, nausea, and breast tenderness with the hormonal IUD
Rare problems include:
Expulsion. An IUD can come out of a girl's uterus by accident (called "expulsion"). Sometimes a girl doesn't know this has happened. The overall risk of expulsion is low, but it is slightly more common in women who have never had a baby.
You can check that an IUD is still in place by feeling for the string (a doctor or nurse practitioner can explain how to do this). It's also good to let a doctor know about any odd vaginal discharge, cramping or pain, fever, or if the length of the IUD string changes.
You will need to go back for a follow-up visit with the doctor within the first 3 months after the IUD is first put in. The doctor or nurse practitioner will check that the IUD is properly in place.
Perforation of the uterus. There's an extremely small (1 in 1,000) risk that an IUD might push through the wall of the uterus while it is being put in.
Pelvic inflammatory disease (PID). There's a very low risk of infection from bacteria getting into the uterus during IUD insertion. Most infections happen within the first 20 days after placement of the IUD.
IUDs are a good birth control option for almost every female. However, IUDs aren't recommended if:
a woman has PID or an active STD infection
a woman is already pregnant or may be pregnant
a woman has problems with her uterus, like a disease or malformation, or if she has abnormal bleeding.
Experts now recommend IUDs as a good birth control option for younger women and teens because they last for many years, require no daily maintenance, and are very effective at preventing pregnancy. A newer type of IUD is smaller and uses a lower dose of progesterone, which may make it a better option for girls who have never had a baby.
How Do You Get It?
An IUD must be inserted into the uterus by a doctor or nurse practitioner. This is often easiest to do during a girl's period, but an IUD can be inserted anytime during a girl's cycle as long as she is not pregnant. Copper IUDs need to be replaced every 10 years, and progesterone IUDs should be replaced every 3-5 years, depending on the brand.
If you're interested in using an IUD, talk to your doctor to see if it's a good birth control option for you.
How Much Does It Cost?
An IUD costs about $400 to $800. That doesn't include the cost of having a doctor or nurse practitioner insert and remove it, as well as follow-up visits — these things cost extra. Many health insurance plans cover the costs, and family planning clinics (such as Planned Parenthood) may charge less.
Because an IUD lasts for many years, the cost of one works out to about the same as monthly birth control methods, such as the Pill or ring.