IUD Side Effects

Written by Nicole Schmidt
Medically Reviewed by Jabeen Begum, MD on June 09, 2025
7 min read

Nearly 4.5 million people in the U.S. use an intrauterine device (IUD) for birth control. They're very effective at preventing pregnancy — only 1 out of every 100 people with an IUD will get pregnant while using the device. Depending on the brand, an IUD can last up to 10 years.

IUDs are also very safe. Some people do have side effects, but serious problems are rare.

Side effects from this birth control method can be different for everyone. The ones you get depend on which type of IUD you have and your medical history.

There’s no way to predict how your body will respond to an IUD. If you do have any problems, it’s important to inform your doctor.

Katharine White, MD, chief of obstetrics and gynecology at Boston Medical Center, says that cramps are the most common IUD side effect. They usually feel like period cramps and can last anywhere from a few hours to a few days. 

“Anything that you would do to help with menstrual cramps can be really helpful,” White says. That might mean taking an over-the-counter pain reliever, such as ibuprofen, soaking in a bath, or using a heating pad or hot water bottle. “Heat is your best friend here,” she adds.

Mild to moderate cramping is normal, but if the pain becomes intense, call your doctor.

Pain is another one of the most common side effects of having an IUD inserted, but the experience varies from person to person. 

White recommends talking to your doctor ahead of time about your concerns and pain management options. They might prescribe an antianxiety medication to help you feel more relaxed or offer a medication called ketorolac, which can ease pain during the procedure. “Think of it as the bigger, stronger cousin of ibuprofen and naproxen,” White says.

In some cases, you may be able to get a paracervical block, an injection that numbs the nerves around the cervix, similar to how novocaine works at the dentist. For people with a history of trauma, it’s possible to have the IUD inserted while you’re sedated, so you’re not awake during the procedure.

Taking the rest of the day off to give yourself time to recover is recommended, White says. “You get to treat yourself on this day, whether it's Netflix on your couch, time with a friend, or whatever else that might look like,” she says.

Some people feel lightheaded or dizzy right after their doctor inserts the IUD. In a few cases, this can cause fainting.

If you start to feel dizzy, lie down and rest until the feeling passes. When you’re ready to get up, do so very slowly.

It’s normal to have some light bleeding in the first few days after getting your IUD. Depending on which type you have — hormonal or copper — your periods may become lighter or heavier. Some people also have spotting or bleeding in between periods. It can take up to six months for your cycle to settle into a normal pattern.

One of the biggest differences between copper and hormonal IUDs — aside from how they change your menstrual cycle — is how long they last. A copper IUD can last up to 10 years, while you usually need to switch a hormonal IUD every three to eight years, depending on the brand. White recommends considering IUD side effects when deciding which IUD is right for you. “The day-to-day is what matters more than the overall duration,” she says.

Mirena IUD side effects

Hormonal IUDs (Kyleena, Liletta, Mirena, and Skyla) work by releasing small amounts of the hormone progestin into your body. Progestin prevents pregnancy by stopping ovulation, the process where your body releases an egg. It also thickens the cervical mucus, which makes it harder for sperm to move through it. Many people who have a hormonal IUD have lighter, shorter, and less painful periods. Sometimes, they stop your periods altogether.

“There are people who are really disabled by period pain, and hormonal IUDs can be an amazing fix for that,” says White. While your period may get lighter, it may also be less predictable.“For the first six months, you just don’t know when bleeding might happen,” she says.

Copper IUD side effects 

The copper IUD (ParaGard) is a nonhormonal birth control option. Copper stops sperm from reaching the uterus. One downside of a copper IUD is that it may make your periods longer, heavier, and icause more cramps. These symptoms often get better after three to six months, but that’s not always the case.

If you have milder periods and don't need pain medication for period pain, “a copper IUD isn’t likely to greatly impair your quality of life,”  White says. You might have some spotting or irregular bleeding at first, but over time, the copper IUD won’t change your overall cycle. “Some people really like that predictability,” she says.

About 1 in 10 people will get fluid-filled sacs, called cysts, in their ovaries in the first year after they get an IUD. Cysts usually go away on their own within three months.

Most ovarian cysts are harmless and don’t cause any symptoms. But some will cause bloating, swelling, or pain in the lower belly. The pain can become sudden or severe if a cyst ruptures. If you notice these symptoms, talk to your doctor.

Your odds of getting pregnant while you have an IUD are very low — about 1%. But if it does happen, it could be dangerous. It raises the risk for:

  • Miscarriage
  • Infection
  • Early labor and delivery

If you get pregnant while you have an IUD, your doctor will likely remove it. There are risks to taking out the IUD while you’re pregnant. Ask your doctor about your options.

This happens when a fertilized egg implants outside your uterus. It’s impossible to continue an ectopic pregnancy, and if it’s not treated, it can be life-threatening.

Getting pregnant while you have an IUD puts you at a slightly higher risk for an ectopic pregnancy. Each year, only 1 out of 1,000 people with an IUD will have one. It may be a little more likely if you had an ectopic pregnancy, pelvic infection, or surgery on your fallopian tubes in the past.

Let your doctor know right away if you notice belly pain or vaginal bleeding. These could be signs of an ectopic pregnancy.

An IUD slightly raises your odds for an infection of the uterus, fallopian tubes, or ovaries, called pelvic inflammatory disease (PID). Bacteria that cause PID can get into your body when the IUD is inserted.

You’re most likely to get the infection in the first 20 days after you get the IUD.

It’s important to treat PID quickly to avoid serious problems. Tell your doctor if you have symptoms such as:

Your doctor will prescribe antibiotics to treat PID.

Rarely, the IUD can poke through the wall of the uterus as your doctor inserts it. You will need to have it removed if this happens.

“One of the important things to know about [perforation] is that it doesn’t threaten your fertility,” White says. “The vast majority of the time, even when this very rare event happens, it doesn’t do damage to anything.”

This is when the IUD falls out of the uterus. It happens in about 3% of women. The risk is slightly higher in women who’ve been pregnant before.

An expulsion causes symptoms such as bleeding and pain, but some women don’t have any symptoms.

If you think your IUD fell out, don’t try to put it back in yourself. See your doctor to see if they recommend replacing it, or if there’s another form of birth control that would work better for you. Until then, use a condom or another backup birth control method.

Can you get pregnant if your IUD moves?

It’s uncommon, but if an IUD shifts out of place, your chances of getting pregnant go up.

Can an IUD damage the cervix?

An IUD won’t damage the cervix. In rare cases, it can puncture the uterus (which is above your cervix). If this happens, you may need surgery.

What are the disadvantages of an IUD?

The downsides of an IUD depend on the type and how your body reacts. Talk to your doctor to figure out which option is best for you.

Do IUDs cause weight gain?

Not typically. Copper IUDs don’t contain hormones, so they won’t affect your weight. Other types, such as the Mirena, do contain hormones, but most studies show they don’t cause weight gain.