Mirena® | How Does It Work

Mirena is more than 99% effective at preventing pregnancy for as long as you want for up to 5 years.

Mirena prevents pregnancy, most likely in several ways:

• Thickens cervical mucus to prevent sperm from entering your uterus

• Inhibits sperm from reaching or fertilizing your egg

• Thins the lining of your uterus

Mirena may stop the release of your egg from your ovary, but this is not the way it works in most cases. While there’s no single explanation for how Mirena works, most likely, the above actions work together to prevent pregnancy for up to 5 years.

Mirena does not protect against HIV or STDs.

As soon as Mirena is placed in your uterus by your healthcare provider, it starts releasing small amounts of the hormone levonorgestrel into your uterus to provide continuous birth control for as long as you want, for up to 5 years.

Mirena and hormones

Mirena is estrogen-free. It releases small amounts of levonorgestrel, a progestin hormone found in many birth control pills, locally into your uterus at a slow and steady rate. Only small amounts of hormone enter your blood.

Mirena may also help treat heavy periods. The hormone in Mirena reduces the monthly thickening of the uterine lining.

Indications & Usage

Mirena (levonorgestrel-releasing intrauterine system) is a hormone-releasing system placed in your uterus to prevent pregnancy for as long as you want for up to 5 years. Mirena also treats heavy periods in women who choose intrauterine contraception.

Important Safety Information About Mirena

Only you and your healthcare provider can decide if Mirena is right for you. Mirena is recommended for women who have had a child.

• Don’t use Mirena if you have a pelvic infection, get infections easily or have certain cancers. Less than 1% of users get a serious infection called pelvic inflammatory disease. If you have persistent pelvic or abdominal pain, see your healthcare provider.

• Mirena may attach to or go through the wall of the uterus and cause other problems. If Mirena comes out, use back-up birth control and call your healthcare provider.

• Although uncommon, pregnancy while using Mirena can be life threatening and may result in loss of pregnancy or fertility.

• Ovarian cysts may occur but usually disappear.

• Bleeding and spotting may increase in the first few months and continue to be irregular. Periods over time may become shorter, lighter or even stop.

Mirena does not protect against HIV or STDs.

Available by prescription only.

You are encouraged to report negative side effects or quality complaints of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.

For important risk and use information about Mirena, please see the Full Prescribing Information.