8 Mirena IUD Side Effects You Should Know About

The Mirena (levonorgestrel) intrauterine device (IUD) is a very effective long-acting birth control option. Once inserted, it’s over 99% effective in preventing pregnancy for up to 7 years. If you’re considering giving Mirena a try, it’s important to know about its possible side effects.

We’ll discuss eight Mirena IUD side effects you should be aware of. Keep in mind that many of them can happen with any IUD, not just Mirena.

1. Pain following IUD insertion

Having an IUD inserted can be uncomfortable and sometimes painful. This side effect can happen with all IUDs, including Mirena. But the good news is that IUD side effects from placement are temporary. The placement procedure itself doesn’t take long, so the most painful part is over within minutes.

After insertion, cramping and spotting can occur and may last for a few weeks. And some people experience temporary nausea and dizziness right after insertion. Medications, like ibuprofen (Advil, Motrin), may help with pain or cramping and make the process more comfortable.

2. Spotting after IUD removal

When Mirena is removed, you may also experience some temporary side effects like spotting and cramping. Again, these side effects can happen with all IUDs, not just Mirena. Eventually, your body and menstrual cycle will return to the way they were before the IUD. So, if Mirena caused period changes, they should return to how they previously were after removal.

It’s important to remember that even if your menstrual cycle hasn’t returned to normal yet, you may still be able to get pregnant right away after Mirena is removed.

3. Breakthrough bleeding

Some people may experience irregular periods and spotting between periods after an IUD is inserted. This IUD side effect is more likely to happen during the first 3 to 6 months after insertion. Sometimes, breakthrough bleeding with Mirena occurs more frequently at first. But it should happen less often as your body adjusts to the device in your uterus.

In the meantime, it can be a good idea to keep period products like sanitary pads handy and wear dark-colored underwear if your cycle is unpredictable. If spotting becomes too bothersome or doesn’t improve after the first 6 months, let your healthcare provider know.

4. Period changes

Over time, your period may become lighter, less frequent, or even disappear completely. As many as 20% of women experience no periods within 1 year after starting Mirena. This may be desirable if you have heavy bleeding. So for some people, this isn’t a bad IUD side effect — it might even be the reason you’re using Mirena.

But lack of a period can make it tough to tell if you’ve become pregnant. If you think you might be pregnant or haven't had a period in 6 weeks, take an at-home pregnancy test or call your healthcare provider. You should also check in with your provider if your periods become heavier than usual, or if bleeding increases after it’s been light for a while.

Keep in mind that period changes only last while you have Mirena inserted. So if this side effect isn’t a positive thing for you, it can be reversed. Your periods should return to their typical pattern after Mirena is removed.

5. Headaches

There’s a well-known link between hormones and headaches. They can be caused by natural hormone changes that happen during your period. But headaches can also happen after starting hormonal birth control. In clinical trials, about 16% of people reported having a headache or migraine while using Mirena.

Occasional, mild headaches can usually be treated with over-the-counter pain relievers. Staying hydrated and getting proper rest can also help manage headaches. But talk to your healthcare provider if you’re having frequent or very painful headaches.

If you already have migraines, IUDs are considered safer than birth control methods that contain estrogen. But keep in mind that it’s difficult to predict if an IUD will affect your migraines. It’s a good idea to keep a headache diary and let your provider know about any new or worsening symptoms.

6. Vaginal irritation

From time to time, most women will experience vaginitis (vaginal inflammation). Symptoms are different for everyone but often include vaginal irritation or discharge. People using an IUD may be more likely to experience these symptoms. In clinical studies, around 10% of Mirena users experienced vaginitis.

If this IUD side effect is bothering you, talk to your healthcare provider. Sometimes vaginitis is mild and goes away on its own. Other times, there may be medications or vaginal lubricants that your provider can recommend to make you more comfortable.

If you notice severe pain or abnormal or foul-smelling vaginal discharge, contact your provider right away. In rare cases, these can be a sign of a serious infection called pelvic inflammatory disease (PID). PID requires medical attention to lower the risk of long-term complications.

7. IUD movement

IUDs need to stay in the uterus to do their job. One of the IUD side effects to be aware of is that they can sometimes move out of place. Examples of IUD movement include:

• Expulsion: when an IUD is pushed partially or fully out of the uterus

• Embedment: when an IUD becomes stuck in the wall of the uterus

• Perforation: when an IUD tears through the wall of the uterus

IUD movement is rare, but it can be serious if it happens. Symptoms include pain and bleeding, but some people experience no symptoms at all. You also aren’t protected against pregnancy if the IUD moves.

The Mirena IUD has two thin threads that hang out of your cervix after it’s been placed. Check these threads once monthly to make sure the IUD is still in place. A change in thread length or not being able to feel them may be signs of movement. Don’t pull on the threads at home if they feel shorter than usual.

Contact your healthcare provider if you think your IUD has moved, even if you’re not having any symptoms. You’ll need to be checked to make sure your IUD is still in place.

8. Ectopic pregnancy

No birth control method can offer a 100% guarantee that you won’t become pregnant. And if you get pregnant after Mirena is inserted, there’s a higher likelihood of an ectopic pregnancy. This is a pregnancy that starts outside of the uterus.

Ectopic pregnancies can be life-threatening. And they can affect your future fertility. Unexpected vaginal bleeding, abdominal pain or cramping, or low back pain can be symptoms of this IUD side effect. Contact your healthcare provider immediately if you have these symptoms or if you become pregnant while Mirena is in place.

When should I contact my healthcare provider about side effects from Mirena?

Most Mirena side effects are mild and get better as your body adjusts to it. Spotting and breakthrough bleeding are common short-term IUD side effects. Periods typically become lighter and happen less often after the first few months with Mirena. Contact your healthcare provider if bleeding remains heavy or gets heavy after being light for a while.

If you experience any symptoms associated with a serious Mirena side effect — such as pain or changes in your threads — contact your healthcare provider right away. These shouldn’t be ignored and may require treatment.

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Written by:

Tegan Smedley, PharmD, APh

Tegan Smedley, PharmD, APh, has 10 years of experience as a pharmacist. She has worked in a variety of settings, including retail, hospital, and ambulatory care.

Edited by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

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