Can you get pregnant on the mirena (levonorgestrel)?

Yes: The Mirena (levonorgestrel) IUD is over 99% effective at preventing pregnancy. To put it another way, the risk of pregnancy is about 1 in 1000. Pregnancy isn't common but it does happen in rare instances. If you do get pregnant while the Mirena (levonorgestrel) is in place, you have a high chance of having an ectopic pregnancy. Best wishes!