Mirena is a plastic device containing the female hormone levonorgestrel. This hormone causes changes in your cervical mucus and uterine lining, making it harder for sperm to reach the uterus and harder for a fertilized egg to attach to the uterus. The Mirena intrauterine device is placed in the uterus where it slowly releases the hormone to prevent pregnancy for up to 5 years. Mirena is meant for use in a woman who has had at least one child and is in a stable sexual relationship with someone who has no other sexual partners.
Mirena is also used in women who have heavy menstrual bleeding and choose to use an intrauterine form of birth control.
An intrauterine device can increase your risk of developing a serious pelvic infection, which may threaten your life or your future ability to have children. Ask your doctor about your personal risk and about ways to help prevent a pelvic infection.
You should not use Mirena if you are allergic to levonorgestrel, silicone, or polyethylene, or if you have:
- abnormal vaginal bleeding;
- an untreated or uncontrolled pelvic infection (vaginal, uterine, or bladder);
- a serious pelvic infection following a pregnancy or abortion within the past 3 months;
- a history of pelvic inflammatory disease (PID), unless you have had a normal pregnancy after the infection was treated and cleared;
- uterine fibroid tumors or other conditions that affect the shape of the uterus;
- past or present breast cancer;
- liver disease or liver tumor (benign or malignant);
- known or suspected cervical or uterine cancer;
- a recent abnormal Pap smear that has not yet been diagnosed or treated;
- a disease or condition that weakens your immune system, such as AIDS, leukemia, or IV drug abuse;
- if you have another intrauterine device (IUD) in place; or
- if you do not have an exclusive sexual partner.
You may need special tests to safely use the Mirena intrauterine device if you have:
- a bleeding or blood-clotting disorder;
- a vaginal infection, pelvic infection, or sexually transmitted disease; or
- high blood pressure, heart disease or a heart valve disorder.
Mirena may be inserted immediately after a first trimester abortion.
Your doctor may ask about your partner’s medical and sexual history before prescribing Mirena for you.
Mirena should not be used during pregnancy. This device can cause severe infection, miscarriage, premature birth, or death of the mother if it is left in place during pregnancy. Tell your doctor right away if you become pregnant while using Mirena.
If you choose to continue a pregnancy that occurs while using Mirena, watch for signs of infection such as fever, chills, flu symptoms, cramps, vaginal bleeding or discharge. Contact your doctor at once if you have any of these symptoms.
If you have recently had a baby and are breast-feeding, wait until your baby is at least 6 weeks old before you start using Mirena.
Get emergency medical help if you have severe pain in your lower stomach or side. This could be a sign of a tubal pregnancy (a pregnancy that implants in the fallopian tube instead of the uterus). A tubal pregnancy is a medical emergency.
Mirena may become embedded into the wall of the uterus, or may perforate (form a hole) in the uterus. If this occurs, the device may no longer prevent pregnancy, or it may move outside the uterus and cause scarring, infection, or damage to other organs. If the device embeds in or perforates the uterine wall, your doctor may need to surgically remove the device.
Call your doctor at once if you have a serious side effect such as:
- severe cramps or pelvic pain;
- extreme dizziness, feeling like you might pass out;
- heavy or ongoing vaginal bleeding, vaginal sores, vaginal discharge that is watery, foul-smelling discharge, or otherwise unusual;
- severe pain in your side or lower stomach;
- pale skin, weakness, easy bruising or bleeding;
- fever, chills, or other signs of infection;
- pain during sexual intercourse;
- sudden numbness or weakness, especially on one side of the body;
- sudden or severe headache, confusion, problems with vision, sensitivity to light;
- jaundice (yellowing of the skin or eyes); or
- signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Less serious side Mirena effects may include:
- irregular menstrual periods, changes in bleeding patterns or flow;
- breakthrough bleeding, or heavier menstrual bleeding during the first few weeks after device insertion;
- back pain;
- headache, nervousness, mild dizziness;
- nausea, vomiting, bloating;
- breast tenderness or pain;
- weight gain, acne, changes in hair growth;
- mood changes, loss of interest in sex;
- mild itching, skin rash; or
- puffiness in your face, hands, ankles, or feet.
This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.