Intrauterine devices

An intrauterine device, or IUD, is a small contraceptive placed inside the uterus by a trained clinician. The uterus is the organ where a pregnancy develops. An IUD is not a disease or a diagnosis.

IUDs provide long-lasting contraception without requiring you to remember a daily pill. They are reversible, meaning a clinician can remove the device if you want to become pregnant or change methods. Fertility usually returns quickly after removal.

There are two main types:

• Copper IUDs contain copper and do not contain hormones
• Hormonal IUDs release a progestogen, a hormone similar to progesterone

Hormonal IUDs are also sometimes called intrauterine systems, or IUSs. Different products remain effective for different lengths of time, so it is important to know which device you have and when it should be removed or replaced.

An IUD does not protect against sexually transmitted infections, or STIs. Condoms can reduce the chance of passing many STIs.

Both types mainly prevent fertilization, when sperm joins an egg.

Copper affects sperm movement and function, making fertilization much less likely. A copper IUD works as soon as it is placed. It can also be used as emergency contraception when inserted within the recommended time after unprotected sex.

A hormonal IUD releases a small amount of progestogen inside the uterus. This thickens mucus at the cervix, the opening of the uterus, making it harder for sperm to pass through. It also thins the uterine lining. Some hormonal IUDs may sometimes suppress the release of an egg, but this is not their main effect.

IUDs do not end an established pregnancy.

Placement usually takes place during an office or clinic visit. A clinician passes the IUD through the cervix and into the uterus. Two thin threads extend through the cervix into the upper vagina. These allow the position to be checked when needed and help a clinician remove the device later.

Cramping or pain can occur during and shortly after placement. Experiences differ. Before the procedure, ask what pain relief is available and what to expect. Local anesthetic may be an option in some settings.

IUDs are among the most effective reversible forms of contraception. Their effectiveness does not rely on remembering something every day or each time you have sex.

The two types can affect menstrual bleeding differently. A copper IUD may make periods heavier, longer, or more painful, especially during the first few months. A hormonal IUD often causes irregular spotting at first. Over time, periods may become lighter or stop.

Some hormonal IUDs are used to treat heavy menstrual bleeding. A lack of periods while using a hormonal IUD does not usually mean that blood is building up inside the body.

An IUD may be suitable for people who have or have not given birth, including adolescents. Whether a particular type is appropriate also depends on your health, medicines, bleeding history, risk of pregnancy, and the shape of your uterus.

A clinician should confirm that pregnancy can reasonably be excluded before placement. STI screening may be offered based on your age and risk. When screening is needed, it can often be performed on the day of placement without waiting for the result. Placement is usually delayed if there is a known current cervical infection or pelvic infection.

Bleeding changes and cramping are common after placement and are not usually dangerous. However, they may be troublesome enough to discuss at routine follow-up.

Other situations related to IUD use include:

• Expulsion: The device partly or completely leaves the uterus, most often during the first months
• Malposition or embedment: The device is not in the intended position or becomes lodged in the uterine wall
• Uterine perforation: The device passes through the wall of the uterus during placement; this is uncommon
• Pelvic infection: Infection can occur after placement, particularly when an untreated STI is present
• Pregnancy: Pregnancy with an IUD is uncommon but requires prompt assessment

If the threads suddenly feel much longer or shorter, or you cannot feel them after previously being able to, the device may have moved. Threads can also curl upward while the IUD remains correctly positioned. Do not pull on them. Use another contraceptive method or avoid sex that could cause pregnancy until a clinician advises whether emergency contraception or a position check is needed.

Take a pregnancy test and seek prompt medical advice if your period is unexpectedly late, you develop pregnancy signs, or you think the IUD may have moved. A pregnancy with an IUD needs assessment to locate the pregnancy and discuss the device safely.

Seek urgent same-day care for fever, worsening pelvic pain, unusual or bad-smelling discharge, or feeling significantly unwell after placement.

Seek emergency care for severe abdominal or one-sided pelvic pain, fainting, shoulder-tip pain, or heavy bleeding, especially with a positive pregnancy test. These can be signs of internal bleeding or an ectopic pregnancy, in which a pregnancy develops outside the uterus.

Before choosing an IUD, ask about the differences between copper and hormonal devices. Your usual bleeding pattern, preference about hormones, need for emergency contraception, and interest in lighter periods can help guide the choice.

Tell the clinician if you might be pregnant, have unexplained bleeding, currently have pelvic pain or unusual discharge, or have been told that the inside of your uterus has an unusual shape. Also discuss relevant medical conditions, including breast cancer when considering a hormonal IUD.

Before placement, you can ask:

• Which exact product is being offered and how long it works
• What pain relief is available during and after placement
• Whether you need STI or pregnancy testing
• When contraceptive protection begins
• What bleeding changes to expect
• What to do if you cannot feel the threads

Keep a record of the product name, placement date, and expected removal or replacement date. Contact the clinic if you lose this information; the duration cannot be identified reliably from the threads alone.

You do not need to check the threads unless you want to or your clinician recommends it. If you choose to check, gently feel high in the vagina for the threads without pulling them. You should not try to remove an IUD yourself.

Routine follow-up is not always required after uncomplicated placement. Arrange a non-urgent appointment if bleeding, pain, or other changes remain difficult to manage, or if you want the device removed. You do not need to justify a request for removal.

Can an IUD move around the body?

An IUD does not normally travel freely through the body. Rarely, it can perforate the uterine wall during placement. Imaging, such as ultrasound or an X-ray, can be used to locate a device when the threads are not visible and its position is uncertain.

Can I use tampons or menstrual cups?

Tampons can generally be used with an IUD. Menstrual cups may carry a risk of accidentally pulling the threads or creating suction during removal. Ask how to release the cup’s seal and avoid catching the threads.

Can a partner feel the threads?

A partner may occasionally notice them, especially soon after placement. The threads often soften and curl over time. A clinician can check them if they remain uncomfortable, but cutting them very short may make removal more difficult.

Does insertion require a period?

Not necessarily. Placement can usually occur at any point in the menstrual cycle when pregnancy can reasonably be excluded. Timing may affect whether backup contraception is needed after placement of a hormonal IUD.

Can an IUD be removed before its scheduled date?

Yes. A trained clinician can remove it at any time. If you do not want to become pregnant, discuss replacement contraception before removal because pregnancy can occur soon afterward.

Does an IUD cause infertility?

The device itself does not cause infertility. An untreated STI can damage the reproductive organs whether or not an IUD is present, which is why testing may be offered based on individual risk.