What are the dangers of using the mirena (levonorgestrel) iud?

Minimal: Pain and cramping with insertion are common, but not dangerous. The chances of you getting an infection may increase slightly. You could get pregnant and not know it. You should expect some spotting for the first year. Perforation of the uterus is very rare. A broken string can require a hysteroscopy to remove it in the future. Cutting the string too short can cause pain for your partner.