Low-Down on the Mirena (Levonorgestrel IUD)

The Mirena IUD is a hormonal intrauterine device that is inserted into the uterus for long-term birth control. Mirena releases a low amount of the progestin, levonorgestrel, continuously over a 5-year period as a way to prevent pregnancy.

IUD strings
Eduardo Luzzatti BuyA / E+ / Getty Images


Mirena is a type of IUD. It is a small, "T-shaped" contraceptive device made of flexible plastic. It measures 32mm across and down.

The Mirena IUD can protect you against pregnancy for up to 5 years, so It is considered to be a long-acting, reversible birth control method.

Your Mirena IUD must be inserted by a qualified healthcare provider. It is also one of the most effective birth control methods available. It is just as effective as a vasectomy!

How It Works

Over the 5 year time period, the Mirena IUD slowly releases a small amount of progestin, levonorgestrel.

Mirena helps to prevent sperm from joining with an egg by affecting how the sperm move. Basically, it interferes with the movement of the sperm toward the egg.

The Mirena IUD can also thicken your cervical mucus — this also makes it more difficult for the sperm to swim. Because this IUD contains progestin, Mirena is slightly more effective than the ParaGard IUD when it comes to preventing pregnancy.

How Quickly Does It Work?

The Mirena IUD works immediately if you have it inserted within 7 days after the start of your period.

If you have your Mirena inserted at any other time during your menstrual cycle, you will need to use a backup birth control method during the first week (7 days) after insertion. You will have pregnancy protection after these 7 days.

Who Can Use It?

Most women can use the Mirena IUD.

The American College of Obstetricians and Gynecologists approve the use of IUDs such as Mirena, Skyla, or ParaGard in both women who have had prior pregnancies and women who have never been pregnant including teenagers.


  • The Mirena IUD can provide continuous pregnancy prevention for 5 years — but it can also be removed anytime within that 5-year period.
  • It is convenient and hassle-free — once inserted, you don’t really have to do anything.
  • Mirena can help protect against pelvic inflammatory disease because it thickens cervical mucus and decreases your monthly period flow.
  • The Mirena IUD can improve your sex life because it lets you be spontaneous.
  • It is an eco-friendly birth control method.
  • Mirena is a good alternative option if you can't use who estrogen-based birth control or other hormonal methods.
  • After the Mirena IUD is removed, your fertility (ability to become pregnant) returns quickly.
  • It is private and discreet birth control method. Nobody can tell if you are using it! 

Non-Contraceptive Benefits

The Mirena IUD can also provide you with certain additional advantages. If you have really painful menstrual cramps, using the Mirena IUD can help lower your pain. Mirena can also reduce the amount of bleeding you have during your period.

Women who use Mirena may see that their menstrual bleeding is reduced by 90 percent. This could lower your risk for anemia.

The Mirena IUD is also the only FDA-approved birth control method that can be used to treat heavy menstrual bleeding.

Side Effects

Most women do not experience any trouble while using Mirena. Some women may have heavy bleeding and cramping during the first few weeks or months after insertion — but healthcare providers can prescribe medication that can lessen these cramps.

As with any progestin-only birth control method, you may experience some side effects. The good news is that, in most cases, these side effects will go away after the first few weeks to months after your Mirena IUD is inserted. Serious problems with Mirena are rare. If you do notice any problems, it is important to tell your healthcare provider right away.


After your 5 years are up, you must have your Mirena IUD removed. You can choose to have another Mirena inserted during the same visit. Never try to remove your Mirena IUD by yourself — it needs to be removed by a medical professional. Also, know that you can have your Mirena removed anytime before the 5-year period ends.

Your Mirena IUD may come out on its own (this is most likely to happen during the first few months after insertion or during your period). Most women don't even realize that their Mirena has come out.

Make a habit of checking your Mirena IUD strings at least once a month (between periods) to ensure it is still in place and protecting against pregnancy.

If you have noticed that your Mirena has come out, you need to contact your healthcare provider to have another one inserted. Your healthcare provider will most likely perform a pregnancy test first — just to make sure that you are not pregnant, before inserting a new Mirena IUD.

Your Mirena IUD could also become partially expelled. If this happens, call your healthcare provider, and use a back-up birth control method (like condoms). Make an appointment, so your healthcare provider can fully take out your Mirena (don't try to pull it out yourself). You can have another Mirena IUD inserted at that time.

Associated Costs 

If you have to pay for your own contraception and you plan to use birth control for at least 1 to 2 years, an IUD is the least expensive option available. The one-time cost of Mirena, when compared to other contraceptive methods, could save you hundreds of dollars or more over time.

Medicaid may cover the cost of your Mirena IUD.

Check with your private health insurance policy as the Mirena IUD should be covered, with no out-of-pocket costs, for all non-grandfathered insurance plans.


The Mirena IUD is one of the most effective reversible methods of birth control available. The Mirena IUD is 99.8 percent effective. This means that out of every 100 women who use Mirena in one year, less than 1 will become pregnant with typical use as well as with perfect use.

Most pregnancies happen to Mirena users when their IUDs slip out without them realizing it.

Even though the chance of pregnancy while using Mirena is extremely low, if it does happen, call your healthcare provider as soon as you realize that you're pregnant.

STD Protection

Mirena offers no protection against sexually transmitted infections. The Mirena IUD does not cause pelvic inflammatory disease or infertility.

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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Nelson AL, Massoudi N. New developments in intrauterine device use: focus on the USOpen Access J Contracept. 2016;7:127–141. doi:10.2147/OAJC.S85755

  2. Centers for Disease Control and Prevention. Effectiveness of family planning methods.

  3. Planned Parenthood. IUD.

  4. Bayer. For women with heavy periods, bleeding may be reduced with Mirena®.