Why does Mirena cause pain?

This device can cause severe infection, miscarriage, premature birth, or death of the mother if left in place during pregnancy. Tell your doctor right away if you become pregnant. If you choose to continue a pregnancy that occurs while using a Mirena IUD, watch for signs of infection such as fever, chills, flu symptoms, cramps, vaginal bleeding or discharge. read more

Serious side effects of Mirena include severe cramps or pelvic pain, heavy or ongoing vaginal bleeding, unusual vaginal discharge, pale skin, easy bruising or bleeding, fever, chills, sudden numbness or weakness, severe headaches, or jaundice (yellowing of the skin or eyes). read more