Intrauterine Device

Additional Resources

Types of IUDs

IUD Comparison
BrandMirena, LilettaSkylaKyleenaParaGard
Length of use5 years (Mirena), 6 years (Liletta)3 years5 years10 years
Hormone52 mg levonorgestrel, which acts on the uterine lining, but causes minimal changes in blood hormone levels.13.5 mg levonorgesterel19.5 mg levonorgestrelNone
How it worksLevonorgestrel thickens cervical mucus and impairs sperm migration to prevent fertilization; may intermittently prevent ovulation.Same as Mirena and Liletta; smaller size.Same as Mirena and Liletta; smaller size.Copper inhibits sperm motility to prevent fertilization.
Effect on periodsPeriods shorter and lighter; periods may be irregular or stop altogether. Good choice for treatment of heavy or painful periods.Periods shorter and lighter, irregular.Periods shorter and lighter; periods may be irregular or stop altogether.Makes periods heavier and crampier.
Ovarian cystIncreased risk of ovarian cysts, most of which often resolve spontaneously.Increased risk of ovarian cysts, most of which often resolve spontaneously.Increased risk of ovarian cysts, most of which often resolve spontaneously.No effect.