An IUD, or intrauterine device, is a small T-shaped device placed inside the uterus to prevent pregnancy. It’s one of the most effective forms of birth control available, preventing pregnancy in over 99% of cases with both typical and perfect use. That puts it far ahead of the pill (91% with typical use) and condoms (82% with typical use). There are two types: hormonal IUDs, which release a small amount of progestin, and one non-hormonal option that uses copper instead.
Hormonal vs. Copper: Two Different Approaches
Hormonal IUDs work primarily by thickening the mucus in your cervix, making it difficult for sperm to enter the uterus and reach an egg. They also thin the uterine lining over time, which is why many people experience lighter periods or no periods at all. The two most well-known hormonal IUD brands in the U.S., Mirena and Liletta, contain the same active ingredient at the same dose and are now approved for up to 8 years of continuous use. Smaller hormonal IUDs like Kyleena and Skyla contain lower doses and last for shorter periods.
The copper IUD, sold as ParaGard in the U.S., takes a completely different approach. It contains no hormones. Instead, the copper interferes with sperm movement, making it harder for sperm to function normally and reach an egg. ParaGard lasts up to 10 years, making it the longest-lasting option. It also doubles as emergency contraception if inserted within five days of unprotected sex.
Who Can Get One
IUDs can be used by people of all ages, including teenagers and people who have never been pregnant. This is a shift from older guidelines that once discouraged IUDs for younger or nulliparous patients (those who haven’t given birth). Current CDC recommendations from 2024 confirm that IUDs are appropriate for both groups. The device is fully reversible: once removed, fertility returns quickly.
What Insertion Feels Like
The insertion process takes only a few minutes but involves several steps that can cause discomfort. Your provider uses an instrument called a tenaculum to steady the cervix, then measures the depth of the uterus with a thin rod called a sound before placing the IUD itself. Pain can occur at each of these steps, and the intensity varies widely from person to person.
There is no single standard approach to pain management during insertion. Over-the-counter anti-inflammatory medications like naproxen don’t reduce pain during the procedure itself, though they can help with cramping afterward. Some providers offer topical or injected lidocaine (a numbing agent), which has mild effectiveness in reducing pain during placement. More advanced options, including oral sedation or IV sedation, are available depending on the clinic and your preferences.
One important thing to know: you can ask your provider to pause or stop the procedure at any time. Clinics increasingly recognize that patients should have clear information about what to expect and real control over the process. Talking through your options beforehand, including what kind of pain relief you’d like, makes a meaningful difference.
How Each Type Affects Your Period
The hormonal and copper IUDs have opposite effects on menstrual bleeding, and this is often the deciding factor when choosing between them.
Hormonal IUDs typically cause lighter, shorter periods. After about three months of use, most people notice significantly less bleeding. Around 20% of Mirena users stop having periods entirely after one year. Irregular spotting is common in the first few months but tends to resolve. For many people, the reduction in bleeding and cramping is a welcome side effect rather than a drawback.
The copper IUD, on the other hand, tends to make periods heavier and cramps more intense, especially in the first several months. This effect can persist for some users. If you already deal with heavy or painful periods, the copper IUD may not be the most comfortable choice. But for people who want long-term, hormone-free contraception, it remains the only IUD option.
Beyond Birth Control
Hormonal IUDs are FDA-approved for treating heavy menstrual bleeding, not just preventing pregnancy. The progestin they release thins the uterine lining over time, which directly reduces menstrual blood flow and cramping. For people with heavy periods who haven’t found relief from other treatments, a hormonal IUD can be a practical, long-term solution that avoids surgery. Providers also commonly recommend hormonal IUDs for managing symptoms of endometriosis and adenomyosis, though these are off-label uses.
Risks and Complications
Serious complications from IUDs are uncommon. The most significant risk during insertion is uterine perforation, where the device punctures the uterine wall. A large study published in The Lancet found this occurs at a rate of roughly 1 to 3.6 per 1,000 insertions. The risk is lowest for people who are not in the postpartum period (about 0.29% over five years) and somewhat higher for those who recently gave birth, particularly while breastfeeding.
Expulsion, where the IUD partially or fully slips out of place, is another possibility. It’s more likely in the first few months after insertion and more common with postpartum placement. You can check that your IUD is in place by feeling for the strings at your cervix. If you can’t find them, or if you feel the hard plastic of the device itself, contact your provider.
There’s a small, temporary increase in infection risk in the first 20 days after insertion, but after that window, IUDs do not raise the risk of pelvic infections. The older reputation of IUDs as infection-prone devices comes from a specific product from the 1970s (the Dalkon Shield) that was pulled from the market. Modern IUDs do not carry that risk.
How Long Each Type Lasts
The duration depends on the specific device:
- Mirena and Liletta (52-mg hormonal): up to 8 years
- Kyleena (smaller hormonal): up to 5 years
- Skyla (smallest hormonal): up to 3 years
- ParaGard (copper): up to 10 years
These are maximum durations. You can have any IUD removed earlier if you want to become pregnant, switch methods, or simply no longer need it. Removal is a quick office visit, typically much less uncomfortable than insertion.