Intrauterine devices (IUDs) are an extremely effective method of birth control. An IUD is a small, T-shaped device that’s placed in your uterus. It must be prescribed by your doctor, who will place it in your uterus during a simple outpatient procedure.

Five brands of IUDs approved by the Food and Drug Administration (FDA) are available today. Mirena, Skyla, Liletta, and Kyleena release hormones to prevent pregnancy. ParaGard contains copper and does not release hormones.

Which one could be right for you? Let’s compare Mirena, Skyla, and ParaGard to explore how these IUDs are similar and different.

Learn about how it feels to have an IUD.

IUDs are long-term birth control. They can stay implanted in your uterus for several years. However, they can be easily removed if you want to become pregnant.

IUDs are made of a plastic called polyethylene. They’re T-shaped, with a string attached to the bottom of the T. The string makes it easier for your doctor to remove the IUD. The string also helps you know that it’s still in place when you check it each month.

Mirena and Skyla

Mirena and Skyla slowly release hormones into your body each day. These hormones can have three different effects to help prevent pregnancy:

  1. They may make you ovulate less often.
  2. They thicken cervical mucus, which makes it harder for sperm to pass into your uterus.
  3. They help prevent sperm from binding to an egg and attaching in your uterus.

Skyla contains 13.5 mg of the progestin hormone levonorgestrel (LNG). About 14 mcg of the hormone is released every day for the first 25 days.

After that, the device releases declining amounts until after 3 years, it’s only releasing about 5 mcg levonorgestrel per day. It should be replaced after 3 years.

Mirena contains 52 mg of levonorgestrel. About 20 mcg of this hormone is released every day when the device is first inserted. The rate drops to about 10 mcg per day after 5 years as it reaches expiration and must be removed or replaced.

Liletta and Kyleena are two other IUDs that slowly release a low dose of hormones into your body.

Liletta contains 52 mg of levonorgestrel, and Kyleena contains 19.5 mg of levonorgestrel. Both release small amounts of levonorgestrel. The amount of LNG released declines over time and the IUD should be removed at year five.

However, these are the newest IUDs, so they haven’t been included in as many studies as the other IUDs. Liletta was approved by the FDA in February 2015. Kyleena was approved in September 2016.


ParaGard doesn’t have any hormones. Instead, it has 176 mg of copper wire coiled around the vertical stem of the T-shape. It also has 68.7 mg of copper wrapped around each side of the horizontal arm.

The copper produces an inflammatory reaction within your uterus. It creates a harmful environment for sperm. This environment helps prevent the sperm from fertilizing an egg and may prevent an egg from attaching in your uterus.

Size28 mm x 30 mm32 mm x 32 mm32 mm x 36 mm
TypeProgestin hormoneProgestin hormoneCopper
Effective for up to3 years5 years10 years
Notable side effectMay cause changes in your periodMay cause changes in your periodMay cause bleeding and discomfort

Mirena and Skyla have the same side effects. You may have changes in your period, such as increased menstrual bleeding, discomfort, or no period at all. You may also have:

With ParaGard, you may have an allergic reaction to the copper. Other side effects include:

All three devices can fall out or shift position. This can increase your risk of pregnancy. They could also tear your uterus. In addition, all three can cause pelvic inflammatory disease, but this is rare. If you have multiple sexual partners, this method of pregnancy prevention is not your best choice.

Learn 11 tips to conquer your IUD side effects.

Study results have shown that these three IUDs have similar effectiveness. Both the copper and hormonal IUDs are more effective at preventing pregnancies than other forms of birth control, besides sterilization.

Overall, IUDs are more than 99 percent effective at preventing pregnancy. This means that less than one in 100 women who use an IUD gets pregnant each year.

One of the main risks of using an IUD is the slight chance that you will have an ectopic pregnancy if you do get pregnant while using it. However, the risk of ectopic pregnancy when you’re not using an IUD is higher.

There is also the small risk that the IUD may shift position or fall out. This can increase the risk of unwanted pregnancy. Learn what to do if your IUD falls out.

Certain conditions can cause problems if you use a hormonal IUD or copper IUD. You should not use any IUD if you have liver disease or if you have or have had the following conditions:

Both hormonal IUDs and the copper IUD are effective methods of birth control. The key differences between Mirena, Skyla, and ParaGard are what they’re made of, how they work, how long they last, and possible side effects.

For instance, Mirena and Skyla release hormones into your body. If you prefer to avoid hormones, you might choose ParaGard.

However, the hormones in Mirena and Skyla are only released in one part of your body. They don’t have the same kind of broad effect as the hormones in birth control pills, which are delivered through your bloodstream.

On the other hand, if you already have heavy bleeding and cramping during your period, you may not want to use ParaGard, which could worsen your bleeding.

To find out more about IUDs, talk to your doctor. They can give you more information about these devices and point you toward an IUD that may work well for you. Be sure to ask your doctor any questions you might have, such as:

  • Are there any benefits to the hormonal IUDs Liletta or Kyleena versus Mirena or Skyla?
  • Is there any reason why I should avoid using an IUD that has hormones?
  • What other long-term birth control options would you suggest for me?

IUDs do not protect against sexually transmitted diseases. Also, because they’re foreign objects, they can increase your chances of getting an infection. You must still use condoms.