Some IUDs are hormonal, but not all of them. There are currently five IUDs available in the U.S., and four of them release a small amount of a synthetic hormone called levonorgestrel. The fifth, ParaGard, is wrapped in copper and contains no hormones at all. Which type you have (or are considering) matters because they work differently, affect your period differently, and last for different lengths of time.
The Four Hormonal IUDs
Mirena, Liletta, Kyleena, and Skyla all release levonorgestrel, a synthetic form of progesterone, directly into the uterus. They differ mainly in how much hormone they contain and how quickly they release it. Mirena starts at about 20 micrograms per day, Liletta at about 18.6, Kyleena at about 17.5, and Skyla at about 14. Over time, those rates drop significantly. By the end of its lifespan, Skyla releases roughly 5 micrograms per day.
These are tiny amounts compared to what you’d get from a birth control pill, and the hormone stays mostly local to the uterus rather than circulating through your entire bloodstream. That’s a key distinction from other hormonal birth control methods like the pill, patch, or ring.
How Hormonal IUDs Prevent Pregnancy
The primary way hormonal IUDs work is by thickening the cervical mucus so much that sperm can’t get through to reach an egg. It essentially creates a physical barrier at the cervical level. As a secondary effect, the hormone also thins the uterine lining, which is why many people experience lighter periods or lose their period entirely while using one.
This thinning of the lining is also why Mirena carries an additional approval beyond contraception: it’s the only IUD specifically approved to treat heavy menstrual bleeding.
The One Non-Hormonal Option
ParaGard is a copper IUD that contains no hormones whatsoever. Instead of levonorgestrel, it has copper wire coiled around its frame, about 176 milligrams on the stem plus additional copper on each arm. Copper ions are released continuously into the uterus, where they interfere with sperm movement and fertilization.
Because it’s hormone-free, ParaGard doesn’t thin the uterine lining or thicken cervical mucus. Your natural menstrual cycle continues. In fact, many people experience heavier, longer, or crampier periods with the copper IUD, especially during the first few months. This is one of the biggest practical differences between the two types: hormonal IUDs tend to make periods lighter or stop them, while the copper IUD can make them heavier.
How Long Each Type Lasts
The higher-dose hormonal IUDs (Mirena and Liletta, which both contain 52 mg of levonorgestrel) are approved for up to 8 years. The Society of Family Planning has recommended that these can be used effectively for 7 to 8 years. Kyleena, with its mid-range dose, is approved for 5 years. Skyla, the lowest-dose option, is approved for 3 years.
ParaGard lasts the longest of any IUD. It’s traditionally approved for 10 years, but clinical guidelines from the Society of Family Planning suggest it remains effective for at least 12 years, and potentially up to 20 years for people who were over 30 when it was placed.
How Periods Change With Each Type
This is often the deciding factor when choosing between hormonal and non-hormonal. With the higher-dose hormonal IUDs like Mirena and Liletta, many people stop getting a period altogether. Lower-dose options like Kyleena and Skyla are more likely to cause lighter monthly bleeding rather than eliminating periods completely. Some irregular spotting is common in the first few months with any hormonal IUD.
With the copper IUD, you keep your natural cycle. Your period arrives on its usual schedule, but it may be noticeably heavier and come with more cramping. For most people this effect is strongest in the first several months and gradually improves, though some experience persistently heavier bleeding for as long as they have the device.
Effectiveness Is Similar for Both Types
Regardless of whether an IUD is hormonal or copper, both types are among the most effective forms of birth control available. In typical use, IUDs have a failure rate of about 1.4 per 100 people over the first year. That’s dramatically better than the pill (5.5 per 100) or condoms (5.4 per 100). At the three-year mark, the IUD failure rate only rises to about 2.1 per 100, while the pill climbs to 15.1 and condoms to 16.0.
The reason IUDs perform so well is simple: once one is placed, there’s nothing to forget. You don’t take it daily, replace it weekly, or use it in the moment. It just works.
Choosing Between Hormonal and Non-Hormonal
If you want lighter periods or have heavy menstrual bleeding, a hormonal IUD pulls double duty as both contraception and period management. If you prefer to avoid synthetic hormones entirely, whether for medical reasons or personal preference, the copper IUD gives you highly effective, long-lasting birth control without altering your hormonal balance.
Both types are reversible. Fertility returns quickly after removal regardless of which type you use or how long it was in place. The choice really comes down to how you feel about hormones and what kind of period experience you’re willing to have.