Every form of hormonal birth control has its own benefits and side effects. The Mirena IUD is no exception.

While some people don’t experience any side effects with their Mirena IUD, others do, and there’s no way to know for sure how it will affect you.

Most side effects taper off over time as your body adjusts. But if you decide Mirena isn’t for you, you can have it removed at any time.

Here’s what you should know about common concerns, listed side effects, and long-term risks.

Can it cause weight gain?

Some people claim that Mirena causes weight gain, but the evidence for this is sparse. It isn’t listed as a common side effect on the Mirena website.

Anecdotal evidence for weight gain — that is, individual stories about gaining weight on the IUD — isn’t very strong.

There are a number of things that can cause weight gain, and it’s difficult to pinpoint one cause without a well-designed study.

Can it affect your mood?

There’s been a lot of discussion about whether there’s a link between IUDs and depression.

In 2016, one of the largest studies on birth control and depression was published. This study looked at data of more than one million participants in Denmark over a period of 14 years. It specifically looked at females ages 15 to 34.

The study noted that 2.2 percent of people who used hormonal birth control methods (including, but not only, the Mirena IUD) were prescribed antidepressants in a year, while 1.7 percent of people who didn’t use hormonal birth control were prescribed antidepressants.

Those who used a hormonal IUD such as Mirena were 1.4 times more likely to be prescribed antidepressants.

That being said, more research is needed to know if there’s a definitive link between hormonal birth control and depression.

It is possible to have depression without being prescribed antidepressants — so that’s one potential flaw in the study. Since there’s stigma against mental illness, some people might not seek medical help for depression at all.

Other research, such as this 2018 review, suggests that progestin-based birth control like Mirena won’t make you depressed.

In conclusion, the research is mixed. If you’re experiencing symptoms of depression and want to seek care, know that you have options.

Can it cause acne?

It probably can.

A 2008 review looked at the safety and side effects of the Mirena IUD. It found that you were more likely to have acne (or have worse acne) after getting an IUD containing Mirena’s main ingredient levonorgestrel.

However, there aren’t any recent papers that examine this link.

Fortunately, there are many home remedies for hormonal acne that could help.

Can it cause breast soreness or tenderness?

Progesterone (a sex hormone produced by the ovaries) is usually associated with tender and sore breasts.

During your menstrual cycle, you’re more likely to experience breast tenderness when progesterone peaks.

Since Mirena works by releasing progestin, a synthetic version of progesterone, it makes sense that it can cause breast tenderness.

However, there’s very little scientific data on how common this side effect is.

Some describe insertion as producing a little discomfort while others find it quite painful — it depends on a range of factors, and you won’t know how it feels until you actually have it inserted.

The FDA notes that you could feel dizzy or even faint during insertion. Cramping is also a common side effect.

Straight after Mirena is inserted, you might feel pain, dizziness, and bleeding. For this reason, it’s a good idea to bring a thermal heat patch, some pads, and ibuprofen along when you get your IUD inserted.

According to the Mirena website, these symptoms should pass within 30 minutes. If they don’t, the IUD could have been inserted incorrectly.

If you’re still experiencing extreme pain and bleeding 30 minutes after insertion, tell your healthcare provider. They might have to examine whether it’s in the right place.

You might experience a little spotting for a few days after the insertion.

If you experience a fever and unexplained pain a few days after insertion, call your doctor. This could be a symptom of sepsis, a life-threatening condition. While this complication is rare, it’s serious.

In the first three to six months of having Mirena, your period may be irregular. You might have heavier or longer periods, as well as spotting.

Your body will adjust to the IUD over the course of six months, with your period possibly becoming even lighter than before insertion.

However, your period may remain irregular. Some people even find that they have little to no bleeding after a few months.

If heavy bleeding continues, talk to your provider.

The Mirena website reports that about 1 in 5 Mirena users have no period at all by the 1-year mark.

At this stage, your period is less likely to be heavy and uncomfortable. Side effects like breast tenderness and acne usually fade after the first year.

However, you might still experience other side effects, such as irregular periods or spotting.

To remove your IUD, your doctor will gently pull the strings of the IUD using forceps or a similar instrument. The Mirena’s arms will fold upward, allowing it to be pulled from the uterus.

You might experience cramping and bleeding during removal of the IUD. However, there are seldom complications with removal.

Your period will usually return and go back to normal within the next few months. Your fertility can return within the next few weeks, so be sure to use another form of contraception if you don’t wish to become pregnant.

The Mirena IUD lasts for five years, after which it will have to be removed or replaced.

If you would like, a new device can be reinserted. The side effects of reinserting Mirena is much the same as the initial insertion.

Some people claim they have less side effects the second time around, but there isn’t any scientific data to back this up.

If your body expelled an IUD before, it’s more likely to expel one again. So, if you want to get Mirena reinserted after expulsion, let your provider know.

You should also let your provider know if you experienced any major symptoms or complications with your IUD.

There are some more serious long-term risks and complications of the Mirena IUD.

While these are more rare than the above-mentioned symptoms, it’s important to be aware that they can happen, and to inform your doctor if you show symptoms of the following conditions.

Ovarian cysts

About 12 percent of people who have a hormonal IUD will develop at least one ovarian cyst in the time that they have the IUD.

Ovarian cysts are usually characterized by:

  • abdominal pain and swelling
  • painful bowel movements
  • nausea and vomiting
  • pain during menstruation
  • pain during intercourse

These cysts usually go away within a month or two, but sometimes they can require medical attention. See a doctor if you think you have an ovarian cyst.

Pelvic inflammatory disease (PID)

Pelvic inflammatory disease is a relatively common condition that affects the reproductive organs.

It’s often caused by a sexually transmitted infection (STI), although it’s possible to get PID without having ever had an STI.

The Centers for Disease Control and Prevention notes that you’re slightly more likely to develop PID in the first 3 weeks after an IUD is inserted.

PID symptoms include:

If you think you’re experiencing symptoms of PID, seek immediate medical attention.

Expulsion

Your uterus can expel your IUD — meaning that it could push it out. Your IUD could also move and get stuck in the wrong place.

This is why it’s important to check your IUD strings. It’s recommended to get in the habit of checking it once a month.

To do this, wash your hands, insert two fingers into your vagina and reach for your cervix. Try to feel the strings, but don’t pull on them.

If you can’t feel your IUD strings, or if they feel longer than usual, see a doctor.

Perforation

While it’s relatively unlikely, it’s possible that an IUD can perforate (tear) your uterus if it’s not in the right place.

You’re more likely to experience a perforation if your IUD is inserted while you’re breastfeeding.

If perforation occurs, your IUD could:

  • be ineffective at preventing pregnancy
  • permanently scar your uterus
  • damage surrounding organs
  • cause an infection

If your IUD perforates your uterus, it will have to be surgically removed.

Pregnancy

Mirena is generally a very effective form of birth control, but it’s possible to get pregnant while on any form of contraception. Only 0.2 percent of 100 Mirena users get pregnant within a year of use.

If you do think you’re pregnant and you have an IUD, it’s essential to let your provider know as soon as possible. Having an IUD inserted during pregnancy can result in a miscarriage, and it can affect your fertility.

The side effects of the Mirena IUD depend a lot on your situation — some people experience certain symptoms while others do not.

If any symptoms are causing you concern, speak to a healthcare provider — preferably the one who inserted your IUD.