An intrauterine device (IUD) is one form of pharmaceutical birth control. While not the most popular form of birth control, IUDs are the most effective form of contraception.

IUD failure rates are 0.8 percent for copper IUDs, and 0.2 percent for hormonal IUDs. These are significantly lower than failure rates for other hormonal methods of contraception, including pills, patches, and shots, which range from 5 – 9 percent failure.

While IUDs are generally safe to use, some women have experienced severe Mirena side effects and complications, and should be aware of any symptoms that could be warning signs of serious problems. Some of these complications have led to the filing of Mirena lawsuits against the manufacturers.

Types of IUD

There are two types of IUDs: copper and hormonal. Both IUD types are popular in the U.S. due to their low maintenance and long efficacy in preventing pregnancy.

Did you know?

An IUD can prevent pregnancy for as long as 12 years depending on the type

Both hormonal and copper IUDs are implanted in the uterus, where they remain for the duration of their use (or until removed due to complications). Once an IUD is inserted, there is no need to take a daily pill, though other contraceptive methods (condoms, spermicide, etc.) can still be employed to increase effectiveness. IUDs offer long-term benefits by preventing pregnancy from 5 – 12 years, depending on the type.

Hormonal IUDs

Hormone-based intrauterine devices use progestin, a synthetic version of the human hormone progesterone, to prevent pregnancy. Specifically, progestin inhibits egg fertilization in three ways:

  • Thickening cervical mucus to trap or block sperm
  • Thinning the uterine wall to prevent egg attachment
  • Preventing ovulation so that no egg is released for the sperm to reach

There are currently four brands of hormonal IUD approved by the U.S. Food & Drug Administration. Three of these – Mirena, Kyleena and Skyla – are produced and marketed by Bayer Pharmaceuticals. The primary difference between each of these three IUDs is the amount of progestin (levonorgestrel) each one releases.

Hormonal IUD Comparison
MirenaKyleenaSkyla & Liletta
Duration: Up to 5 years

Release Rate:

  • 20 mcg/day after 24 days
  • 10 mcg/day after 5 years
Duration: Up to 5 years

Release Rate:

  • 17.5 mcg/day after 24 days
  • 7.4 mcg/day after 5 years
Duration: Up to 3 years

Release Rate:

  • 14 mcg/day after 24 days
  • 5 mcg/day after 3 years

Hormonal IUDs can be removed at any time, such as if the woman wants to become pregnant or if there are complications or side effects from the device.

Mirena IUDs

Bayer markets Mirena IUDs as a safe, hormone-releasing device that can inhibit pregnancy for up to five years. Initially approved by the FDA in 2000, the device is primarily recommended for women who have previously had a child, although women who have not had any children may receive a prescription for Mirena as well.

In addition to being used as a contraception, Mirena contains hormones that will treat heavy menstrual flow in women who are already using intrauterine devices as a contraceptive. (It should not be used to prevent heavy bleeding that may be experienced with other forms of contraception.)

Kyleena IUDs

In many ways, Kyleena IUDs are similar to Mirena IUDs in that they also are marketed by Bayer as being able to prevent pregnancy for up to five years. Also approved in the year 2000 by the FDA, the biggest difference between Kyleena and Mirena is that Kyleena is not indicated for women who have previously given birth.

Unlike Mirena, Kyleena devices do not have a secondary approval for treating heavy menstrual bleeding when using an intrauterine contraceptive device. Women who experience heavy bleeding while using Kyleena should discuss the side effect with their doctor, who may suggest switching to Mirena or another IUD.

Skyla IUDs

Similar to Mirena and Kyleena, Skyla is also promoted by Bayer for use as an intrauterine contraceptive. The biggest difference between Skyla and Bayer’s other two IUDs is the timeframe: Skyla is only to be used for three years, versus the five-year length of use for the other two devices.

Like Kyleena, there is no recommendation in the Skyla prescribing information for use by women who have previously had a child. Skyla also does not contain any type of treatment for controlling the weight of menstruations while in use.

Liletta IUDs

Produced and marketed by Allergan, Liletta is the primary competitor to Mirena, Kyleena and Skyla IUDs. Although it is made by a different company, Liletta uses the same hormone (levonorgestrel) as the other three IUD contraceptive products, and as a result it has very similar risk for complications and side effects as the others.

Liletta IUDs contain enough hormones to prevent pregnancy for up to four years, after which time it will need to be removed or replaced. There are no recommendations about whether women who have had a child should use it, and the Liletta device does not help control menstrual bleeding in the way that Mirena does.

Copper IUDs

Copper intrauterine devices, sometimes known as intrauterine coils, do not use any hormones. Rather, the copper in the IUD acts a spermicide, and it may also help to impede implantation of the fertilized eggs.

The only copper IUD approved by the FDA is ParaGard. It is effective as a contraceptive for up to 10 years, with some studies showing effectiveness for as long as 12 years. Like hormonal IUDs, copper IUDs can be removed at any time.

IUD Safety Concerns

As with many types of medical devices, IUDs carry with them a unique set of safety issues. These can come in the form of severe side effects and complications, as well as misconceptions about the device that can lead to unsafe practices or uses. Read about common birth control myths.

Some existing medical or physiological conditions can increase the likelihood of IUD complications or ineffectiveness. These include:

  • Sexually transmitted diseases (STDs)
  • Pelvic infections (especially within 3 months of childbirth or an abortion)
  • Pregnancy
  • Untreated uterine or cervical cancer
  • Vaginal bleeding (excluding menstruation)

In addition to the potential for complications, some people may misunderstand the purpose of IUDs. For example, IUDs will not protect against sexually transmitted diseases or infections, so other prophylactic precautions should be made to prevent such transmissions.