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Safety and Side Effects

Mirena® isn’t right for everyone. You and your healthcare provider will review your health history to determine if Mirena is an option for you. An important part of your decision is making sure you’re aware of possible side effects. Keep reading to learn about the safety considerations for Mirena. If you have questions or concerns, always talk to your healthcare provider. 

Do not use Mirena if you:

  • are or might be pregnant; Mirena cannot be used as an emergency contraceptive

  • have a serious pelvic infection called pelvic inflammatory disease (PID) or have had PID in the past unless you have had a normal pregnancy after the infection went away

  • have an untreated pelvic or genital infection now

  • have had a serious pelvic infection in the past 3 months after a pregnancy

  • can get infections easily. For example, if you:

    • have multiple sexual partners or your partner has multiple sexual partners

    • have problems with your immune system

    • use or abuse intravenous drugs

  • have or suspect you might have cancer of the uterus or cervix

  • have bleeding from the vagina that has not been explained

  • have liver disease or a liver tumor

  • have breast cancer or any other cancer that is sensitive to progestin (a female hormone), now or in the past

  • have an intrauterine device in your uterus already

  • have a condition of the uterus that changes the shape of the uterine cavity, such as large fibroid tumors

  • are allergic to levonorgestrel, silicone, polyethylene, silica, barium sulfate or iron oxide


Before having Mirena placed, tell your healthcare provider if you:

  • have any of the conditions listed above

  • have had a heart attack

  • have had a stroke

  • were born with heart disease or have problems with your heart valves

  • have problems with blood clotting or take medicine to reduce clotting

  • have high blood pressure

  • recently had a baby or are breastfeeding

  • have severe headaches or migraine headaches

  • have AIDS, HIV, or any other sexually transmitted infection


Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Pregnant woman with pregnancy bump

What if I become pregnant while using Mirena?

Call your healthcare provider right away if you think you may be pregnant. If possible, also do a urine pregnancy test. If you get pregnant while using Mirena, you may have an ectopic pregnancy. This means that the pregnancy is not in the uterus. Unusual vaginal bleeding or abdominal pain may be a sign of ectopic pregnancy.


Ectopic pregnancy is a medical emergency that often requires surgery. Ectopic pregnancy can cause internal bleeding, infertility, and even death.


There are also risks if you get pregnant while using Mirena and the pregnancy is in the uterus. Severe infection, miscarriage, premature delivery, and even death can occur with pregnancies that continue with an intrauterine device (IUD). Because of this, your healthcare provider may try to remove Mirena, even though removing it may cause a miscarriage. If Mirena cannot be removed, talk with your healthcare provider about the benefits and risks of continuing the pregnancy and possible effects of the hormone on your unborn baby.


If you continue your pregnancy, see your healthcare provider regularly. Call your healthcare provider right away if you get flu-like symptoms, fever, chills, cramping, pain, bleeding, vaginal discharge, or fluid leaking from your vagina. These may be signs of infection.

3 to 6 months Icon

How will Mirena change my periods?

For the first 3 to 6 months, your period may become irregular and the number of bleeding days may increase. You may also have frequent spotting or light bleeding, and some women have heavy bleeding during this time. You may also have cramping during the first few weeks. After you have used Mirena for a while, the number of bleeding and spotting days is likely to lessen. For some women, periods will stop altogether. When Mirena is removed, your menstrual periods should return.


In some women with heavy bleeding, the total blood loss per cycle progressively decreases with continued use. The number of spotting and bleeding days may initially increase but then typically decreases in the months that follow. 

Woman holding child breastfeeding

Is it safe to breastfeed while using Mirena?

You may use Mirena when you are breastfeeding. Mirena is not likely to affect the quality or amount of your breast milk or the health of your nursing baby. However, isolated cases of decreased milk production have been reported. The risk of Mirena going into the wall of the uterus (becoming embedded) or going through the wall of the uterus is increased if Mirena is inserted while you are breastfeeding. 


What are the possible side effects of Mirena?

Mirena can cause serious side effects, including:

  • Ectopic pregnancy and intrauterine pregnancy risks. There are risks if you become pregnant while using Mirena.

  • Lif­e‐threatening infection. Lif­e‐threatening infection can occur within the first few days after Mirena is placed. Call your healthcare provider immediately if you develop severe pain or fever shortly after Mirena is placed.

  • Pelvic inflammatory disease (PID). Some IUD users get a serious pelvic infection called pelvic inflammatory disease. PID is usually sexually transmitted. You have a higher chance of getting PID if you or your partner has sex with other partners. PID can cause serious problems such as infertility, ectopic pregnancy or pelvic pain that does not go away. PID is usually treated with antibiotics. More serious cases of PID may require surgery including removal of the uterus (hysterectomy). In rare cases, infections that start as PID can even cause death. Tell your healthcare provider right away if you have any of these signs of PID: long-lasting or heavy bleeding, unusual vaginal discharge, low abdominal (stomach area) pain, painful sex, chills, fever, genital lesions or sores.

  • Perforation. Mirena may go into the wall of the uterus (become embedded) or go through the wall of the uterus. This is called perforation. If this occurs, Mirena may no longer prevent pregnancy. If perforation occurs, Mirena may move outside the uterus and can cause internal scarring, infection, or damage to other organs, and you may need surgery to have Mirena removed. Excessive pain or vaginal bleeding during placement of Mirena, pain or bleeding that gets worse after placement, or not being able to feel the threads may happen with perforation. The risk of perforation is increased if Mirena is inserted while you are breastfeeding, or if you have recently given birth.

  • Expulsion. Mirena may come out by itself. This is called expulsion. Excessive pain or vaginal bleeding during placement of Mirena, pain or bleeding that gets worse after placement, or not being able to feel the threads may happen with expulsion. You may become pregnant if Mirena comes out. If you think that Mirena has come out, avoid intercourse or use a non-hormonal back-up birth control (such as condoms or spermicide) and call your healthcare provider. The risk of expulsion is increased with insertion right after delivery or second-trimester abortion.


Common side effects of Mirena include:

  • Pain, bleeding, or dizziness during and after placement. If these symptoms do not stop 30 minutes after placement, Mirena may not have been placed correctly. Your healthcare provider will examine you to see if Mirena needs to be removed or replaced.

  • Changes in bleeding. You may have bleeding and spotting between menstrual periods, especially during the first 3 to 6 months. Sometimes the bleeding is heavier than usual at first. However, the bleeding usually becomes lighter than usual and may be irregular. Call your healthcare provider if the bleeding remains heavier than usual or increases after it has been light for a while.

  • Missed menstrual periods. About 2 out of 10 women stop having periods after 1 year of Mirena use. If you have any concerns that you may be pregnant while using Mirena, do a urine pregnancy test and call your healthcare provider. If you do not have a period for 6 weeks during Mirena use, call your healthcare provider. When Mirena is removed, your menstrual periods should return.

  • Cysts on the ovary. Some women using Mirena develop a painful cyst on the ovary. These cysts usually disappear on their own in 2 to 3 months. However, cysts can cause pain and sometimes cysts will need surgery.


Other common side effects include:

  • abdominal or pelvic pain

  • inflammation or infection of the outer part of your vagina (vulvovaginitis)

  • headache or migraine

  • vaginal discharge


This is not a complete list of possible side effects with Mirena. For more information, ask your healthcare provider. Tell your healthcare provider if you have any side effect that bothers you or does not go away.


Call your healthcare provider for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 (1-800-332-1088), or visit www.fda.gov/medwatch. You may also report side effects to the manufacturer at 1-888-842-2937.


Every individual responds differently to medication, so talk to your healthcare provider about your individual risk factors and to see if Mirena is right for you.


Mirena does not protect against STIs (sexually transmitted infections) or HIV. So, if while using Mirena you think you or your partner might be at risk of getting an STI, use a condom and call your healthcare provider.

After Mirena has been placed, when should I call my healthcare provider?

If Mirena is accidentally removed and you had vaginal intercourse within the preceding week, you may be at risk of pregnancy, and you should talk to a healthcare provider.


Call your healthcare provider if you have any concerns about Mirena. Be sure to call if you:

  • think you are pregnant

  • have pelvic pain, abdominal pain or pain during sex

  • have unusual vaginal discharge or genital sores

  • have unexplained fever, flu-like symptoms or chills

  • might be exposed to sexually transmitted infections (STIs)

  • are concerned that Mirena may have been expelled (came out)

  • cannot feel Mirena's threads

  • develop very severe or migraine headaches

  • have yellowing of the skin or whites of the eyes. These may be signs of liver problems

  • have had a stroke or heart attack

  • become HIV positive or your partner becomes HIV positive

  • have severe vaginal bleeding or bleeding that concerns you


Prepare for a chat about birth control options with your healthcare provider

Use this list of questions to help guide your conversation at your next appointment.

Download Discussion Guide
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Mirena® (levonorgestrel-releasing intrauterine system) is a hormone-releasing IUD that prevents pregnancy for up to 8 years. Mirena also treats heavy periods for up to 5 years in women who choose intrauterine contraception.



  • If you have a pelvic or genital infection, get infections easily, or have certain cancers, don't use Mirena. Less than 1% of users get a serious pelvic infection called pelvic inflammatory disease (PID).
  • If you have persistent pelvic or stomach pain, or excessive bleeding after placement, tell your healthcare provider (HCP). If Mirena comes out, call your HCP and avoid intercourse or use non-hormonal back-up birth control (such as condoms or spermicide). Mirena may go into or through the wall of the uterus and cause other problems.
  • Pregnancy while using Mirena is uncommon but can be life threatening and may result in loss of pregnancy or fertility.

  • Ovarian cysts may occur but usually disappear.
  • Bleeding and spotting may increase in the first 3 to 6 months and remain irregular. Periods over time usually become shorter, lighter, or may stop.


Mirena does not protect against HIV or STIs.


Only you and your HCP can decide if Mirena is right for you. Mirena is available by prescription only.


For important risk and use information about Mirena, please see Full Prescribing Information.