The term IUD stands for intrauterine device. It is one of many forms of contraception available to women for preventing pregnancy. An IUD is typically a small t-shaped device the size of a quarter that is inserted inside the uterus. Both the copper IUD and the hormonal IUD prevent pregnancy by changing the way sperm cells move, preventing them from reaching and fertilizing an egg.

Mirena, Skyla, Liletta, and Kyleena are the brand names of the four types of hormonal IUDs currently approved in the US. They differ based on how much progestin is released daily and how long they last—ranging from 3 to 6 years—but they are all over 99% effective at preventing pregnancy.

For the time being, there is only one non-hormonal IUD. Paragard is the brand name for the copper IUD. The main difference is that Paragard does not have any hormones working to prevent pregnancy. Instead the copper wrapped around the stem of the device impairs sperm mobility. Sperm does not react well with copper, causing the sperm to become paralyzed and lose its ability to make its way into the womb. ParaGard is also over 99% effective at preventing pregnancy and lasts up to 12 years.

All forms of the IUD contraceptive are equally effective at preventing pregnancy.

There is no form that is particularly safer or more effective than the other. However, it is important to note that the different types of IUDs have varying symptoms, and not all women experience the same symptoms. It is all based upon one’s own personal preference and what they feel most comfortable with. It is important to consult with your healthcare provider to determine which form of contraceptive is right for you. And remember, no IUD protects against any sexually transmitted infections.