Skyla vs. Mirena IUD: Side Effects, Pros, and Cons Compared

Four strengths of hormonal intrauterine devices (IUDs) are available as highly effective options for birth control. These IUDs release a small amount of levonorgestrel, a lab-made form of progesterone. This helps prevent pregnancy and can also control heavy menstrual bleeding.

Two of the available hormonal IUDs are the Skyla IUD and Mirena IUD. Many women like these IUDs because their periods lighten, or stop altogether. And they don’t have to worry about a birth control method for years. But what’s the difference between them?

What is the Skyla IUD?

Skyla is an IUD that’s inserted into your uterus by a healthcare provider at their office. The Skyla IUD releases a low dose of levonorgestrel (14 mcg per day) to prevent pregnancy and can remain in place for up to 3 years.

Skyla is over 99% effective at preventing pregnancy. Skyla works as a birth control method in a few ways:

• It thickens cervical mucus, making it harder for sperm to reach an egg.

• It creates a toxic environment for sperm, lowering the number of sperm that reach an egg.

• It thins the lining of the uterus, making it harder for a fertilized egg to implant and start a pregnancy.

Side effects of Skyla

With the Skyla IUD, side effects can occur. Changes to your periods or spotting are common. This usually resolves within the first 6 months after insertion.

Other common Skyla IUD side effects include:

• Pain or bleeding after placement

• Menstrual cramps

• Lower stomach pain

• Headaches

• Acne

• Breast pain

• Pain around the vagina and vulva

More rare but serious side effects include:

• Expulsion (when your body pushes the IUD back out)

• A higher risk of ectopic pregnancy

• Pelvic inflammatory disease (PID)

• Tear of the uterine wall

It’s important to know what warning signs to watch for, to help catch and manage these serious side effects early. Contact your healthcare provider if you’re experiencing any of the following:

• Fever or chills

• Severe abdominal or pelvic pain

• New or worse pain during sex

• Unusual vaginal discharge

• Heavy vaginal bleeding

• Believe you may be pregnant

Every IUD will have one or two small threads attached to the bottom of it. These threads will hang out of your cervix and into your vagina. You should check for them about once a month to make sure your IUD is still in place. If you cannot feel the threads or they’ve changed in length, give your healthcare provider a call.

Pros and cons of the Skyla IUD

What is Mirena?

Mirena is another hormonal IUD that releases levonorgestrel after it’s inserted into the uterus. Mirena releases a higher dose of hormones (20 mcg per day) than the Skyla IUD. This allows Mirena to be used for birth control for up to 7 years. It works the same way as Skyla and is over 99% effective for preventing pregnancy as well. But, unlike Skyla, Mirena is also FDA-approved to treat heavy periods for up to 5 years. 

In recent years, researchers have investigated whether Mirena can be used as an emergency contraceptive (EC) after unprotected sex. Current clinical studies show that it may be an effective choice. But, the use of Mirena as an EC is considered off-label, which means it has not been FDA-approved to be used in this way. 

Mirena side effects

Because the Mirena IUD releases the same hormone as Skyla, the possible side effects are similar for both IUDs. But, it’s more common for women who use Mirena to stop getting their period after the first year of use. For many women, especially those who experience heavy or painful periods, this may be a welcome side effect.

Mirena also has the same serious side effects, like PID. But like Skyla, these risks are very rare. Mirena will also have small threads that hang out of the cervix. Be sure to check for these threads once a month to make sure the IUD hasn’t moved out of place.

Pros and cons of the Mirena IUD

Mirena vs. Skyla: Which one is better for you?

While choosing a birth control method is a personal decision, it can be helpful to see the basics of the available choices to help you compare options. Below are some key differences between Mirena and Skyla.

What do the two IUDs have in common?

Although there are some noticeable differences between Mirena and Skyla, there are many similarities. These two IUDs have the following in common:

• Effectiveness. Both are over 99% effective at preventing pregnancy.

• Flexibility. Either IUD can be removed whenever you’d like. They don’t have to remain in place for the full amount of time that they’re effective.

• Cost. IUDs can cost anywhere from $500 to $1,300 dollars without insurance. The good news is that many insurance companies provide coverage for IUDs. Check with your plan before making your appointment so they can explain how much you may be expected to pay.

• Local effects. The levonorgestrel in the IUDs primarily affects local tissues. This means less progestin is absorbed into your bloodstream than with other types of hormonal birth controls (e.g., pills, patches).

• Similar side effects. The Mirena and Skyla IUDs are linked to similar side effects, such as acne and breast pain.

• Can stop periods. Both Mirena and Skyla can lighten or put a stop to menstrual periods.

• Breakthrough bleeding. Spotting and irregular bleeding after insertion can occur with both IUDs, and usually resolve within 3 to 6 months.

How does Kyleena compare to the Skyla IUD?

Kyleena and the Skyla IUD are very similar, except that Kyleena releases a higher amount of levonorgestrel (17.5 mcg per day). The higher hormone level in Kyleena allows it to be used for birth control for up to 5 years. 

Kyleena is also over 99% effective for preventing pregnancy, just like Skyla. They’re both the same size (28 mm wide and 30 mm long). They also have the same side effect profile with similar rates of occurrence.

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Written by:

Kristine Foley, PharmD

Kristine Foley is a licensed pharmacist with over 13 years of community pharmacy experience. She earned her Doctor of Pharmacy degree from Rutgers University.

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:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

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