What is an IUD?

IUDs are small, usually T-shaped devices made of flexible plastic or copper. In a short, simple medical procedure, a doctor or healthcare provider places the device inside the uterus. After placement, an IUD provides continuous pregnancy protection for several years.

There are two main types of IUDs:

  • Hormonal IUD: This type of IUD works by releasing a small amount of the hormone progestin. Four brands of hormonal IUDs are available today in the U.S.: Mirena®, Liletta, Kyleena®, and Skyla®.
  • Copper IUD: ParaGard® (copper IUD) is a hormone-free IUD wrapped in a small piece of copper. The copper causes sperm to avoid the area around the IUD. Because the copper helps stop sperm from reaching an egg, the IUD prevents pregnancy.

What is the Mirena® IUD?

Mirena® is a hormonal IUD. The device releases a small amount of the hormone progestin into the uterus. Of the four brands of hormonal IUDs, Mirena® was the first to become available. It provides longer-lasting pregnancy protection than other hormonal IUDs — up to five years compared to three or four years for other brands. Studies show that Mirena® can be effective for up to seven years, even though it is approved to be used for only five years. Liletta is an IUD that is very similar to Mirena®. They are both made with the same type and dose of progestin, so they work the same way. Liletta is approved for up to four years of use.

Mirena® birth control prevents pregnancy by thickening cervical mucus. This makes it more difficult for the sperm to reach an egg. Women who use Mirena® may also have a thinner uterine lining. Having a thinner uterine lining helps protect against uterine cancer.

Because Mirena® uses hormones, your period may come less frequently or stop entirely. This is considered a benefit of Mirena®; having less (or no) bleeding is not considered harmful. Sometimes doctors recommend Mirena® as a way to help women manage heavy or painful periods. This IUD may also improve endometriosis or fibroid symptoms.

How effective is the Mirena® IUD?

Mirena® is more than 99% effective. Out of 10,000 women who use Mirena® for birth control, approximately six may get pregnant unintentionally. Outside of abstinence (not having sex), IUDs are significantly more effective than most common forms of birth control options:

  • Shot (Depo-Provera or Depo shot): 94% effective (i.e. 6 out of 100 women using Depo-Provera can get accidentally pregnant if they don’t come in for their shots regularly).
  • Pill, patch, and vaginal ring: 91% (9 out of 100 women using these methods can have unintended pregnancy if they don’t use these methods properly and consistently).
  • Condoms: 85% (15 out of 100 women using only condoms for birth control will get pregnant each year).

What makes IUDs so effective?

In large part, they offer less room for error. After IUD placement, the device works continuously without any more action or thought from you.

What are common side effects of Mirena®?

The most common side effects of Mirena® happen during or shortly after IUD placement. These effects tend to go away on their own. In the week after IUD placement, some women experience:

Rarely, IUDs may cause other, sometimes severe side effects such as:

  • Pelvic inflammatory disease (PID). This infection of the uterus or nearby reproductive tissues requires medical attention. It is important to know that the risk of PID may be increased for only up to 4 weeks after the procedure. After one month, women using an IUD are at no higher risk of infection as compared to women who do not use an IUD. Using a condom is an important way to help minimize infection risk.
  • Placement issues, such as problems that occur when placing or removing the IUD device.

What are the benefits of IUD birth control?

There are many advantages to using IUDs for birth control. In general, IUD contraception is:

  • Effective: More than 99% effective, IUDs are one of the most effective forms of birth control available today.
  • Safe: IUDs are considered safe for most women. If a doctor advised you against taking the birth control pill due to certain medical conditions, such as high blood pressure, you may still benefit from an IUD.
  • Long term: A healthcare provider places the IUD in a short, nonsurgical office procedure. After placement, the device works for 3 to 10 years (and likely even up to 12 years), depending on the specific IUD.
  • Reversible: Pregnancy protection ends right after IUD removal. You can get pregnant as early as the same day the device is removed.

What are the risks of IUD birth control?

While IUDs are safe for most women, they aren’t for everyone. Certain health conditions may increase the risk of IUD complications, including:

Getting pregnant with an IUD is uncommon but possible. You should seek medical care if you have any reason to believe you may be pregnant when you have an IUD.

Is a Mirena® IUD the right birth control for me?

IUDs are appropriate for most women, especially those looking for the most effective methods of birth control. If you know planning for a baby isn’t in your near future, an IUD may make sense for you.

Some women using Mirena® stop getting their period about 6 months after placement. For women who prefer to get their period every month, a nonhormonal IUD is also an option.

IUDs are effective at preventing pregnancy. They do not prevent sexually transmitted diseases or HIV/AIDS. Your doctor can help you devise a birth control plan that works for your specific needs and circumstances.

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