An intrauterine device (IUD) is a small, T-shaped contraceptive that’s placed inside the uterus to prevent pregnancy. It’s one of the most reliable and low-maintenance birth control options available today. Depending on the type, an IUD can remain effective for several years—and can be removed anytime if you decide to get pregnant.

Unlike daily pills or short-term methods, IUDs offer a “set it and forget it” approach. Once inserted, they work continuously to stop sperm from reaching or fertilizing an egg.

There are two main types of IUDs: copper IUDs and hormonal IUDs. Each type functions differently but shares the same purpose—long-lasting, reversible pregnancy prevention.

How IUDs Work

Both types of IUDs work primarily by interfering with sperm movement. When inserted into the uterus, an IUD creates an environment that makes it nearly impossible for sperm to fertilize an egg.

copper IUDs release small amounts of copper, which is toxic to sperm and changes cervical mucus, preventing sperm from surviving long enough to reach an egg.

hormonal IUDs, on the other hand, release progestin, a hormone that thickens cervical mucus to block sperm and thins the uterine lining to prevent implantation.

In both cases, the IUD acts locally within the uterus—so your body’s overall hormone balance remains largely unaffected.

Types Of IUDs

There are two primary IUD categories, and understanding how they differ helps you choose the right one for your lifestyle and body.

Copper IUDs

Copper-bearing IUDs are made of flexible plastic wrapped with thin copper wire, sometimes called a “copper coil.” They are entirely hormone-free.

The copper continuously releases ions that alter uterine and cervical conditions, creating a hostile environment for sperm. This prevents fertilization naturally without affecting ovulation or hormone cycles.

duration and effectiveness
Copper IUDs can last up to 10 years, making them one of the longest-lasting birth control options available. They begin working immediately after insertion.

They also serve as emergency contraception when inserted within five days after unprotected sex—offering 99% effectiveness in preventing pregnancy.

Hormonal IUDs

Hormonal IUDs, also known as levonorgestrel-releasing IUDs, are made of plastic and contain a reservoir that releases small amounts of the hormone progestin over time.

Progestin thickens cervical mucus to block sperm, thins the uterine lining to prevent implantation, and sometimes stops ovulation.

onset and duration
Hormonal IUDs take about seven days to become fully effective after insertion, so backup contraception is needed during that first week. Depending on the brand, they can last three to eight years.

FDA-Approved IUD Brands

The U.S. Food and Drug Administration (FDA) has approved five IUD brands, each varying slightly in hormone content and lifespan:

  • Paragard: Copper IUD – effective for up to 10 years

  • Mirena: Hormonal IUD – effective for 8 years

  • Liletta: Hormonal IUD – effective for 8 years

  • Kyleena: Hormonal IUD – effective for 5 years

  • Skyla: Hormonal IUD – effective for 3 years

Your healthcare provider can help determine which option best suits your body, lifestyle, and family planning goals.

Benefits Of IUDs

IUDs have become increasingly popular over the past few decades. About 14% of people with female reproductive systems currently use an IUD, and the number continues to rise.

long-term protection
Depending on the type, an IUD offers 3–10 years of pregnancy prevention—no daily pills or reminders needed.

localized hormones
Hormonal IUDs act mainly inside the uterus, minimizing the systemic side effects sometimes seen with other hormonal methods like pills or injections.

emergency contraception
Copper IUDs can double as emergency contraception when inserted shortly after unprotected sex.

lighter periods
Many users of hormonal IUDs notice lighter menstrual bleeding or no periods at all.

reduced cancer risk
Studies suggest that hormonal IUDs may lower the risk of endometrial cancer in certain individuals.

Risks And Potential Complications

While IUDs are very safe, they aren’t entirely risk-free. Some users may experience mild side effects or rare complications.

pregnancy risk
Even though IUDs are more than 99% effective, there’s still a small chance of pregnancy. If pregnancy occurs, the device should be removed immediately to reduce the risk of miscarriage or infection.

ectopic pregnancy
If pregnancy happens while an IUD is in place, the likelihood of an ectopic pregnancy (implantation outside the uterus, usually in a fallopian tube) increases. This condition requires urgent medical attention.

uterine embedding or perforation
In rare cases, an IUD may become embedded in the uterine wall or perforate it during insertion. Surgical removal might be necessary in these uncommon situations.

expulsion
Sometimes an IUD can partially slip out of the uterus, especially within the first year after placement. This requires evaluation by a healthcare provider.

Effectiveness Of IUDs

IUDs are among the most effective reversible contraceptives available. Their success rate rivals that of sterilization.

  • Copper IUD: 99.2% effective (failure rate ~0.08%)

  • Hormonal IUDs: 99.8% effective (failure rate ~0.02%)

These rates make IUDs one of the most reliable options for those seeking long-term, maintenance-free contraception.

The Insertion Process

You can have an IUD inserted at any time during your menstrual cycle, as long as you aren’t pregnant. Some providers may ask for a pregnancy test beforehand and may also screen for sexually transmitted infections before placement.

after childbirth or miscarriage
An IUD can be inserted immediately after giving birth, after an abortion, or following a miscarriage, depending on your recovery.

what to expect during insertion
The procedure typically takes place in a clinic and lasts only a few minutes:

  • Your cervix will be cleaned with an antiseptic solution.

  • The IUD will be inserted through the cervix into the uterus using a thin applicator.

  • Two small strings attached to the device will remain in your vagina. These strings help you and your provider confirm placement and allow for easy removal later.

Some mild discomfort, cramping, or dizziness is normal after insertion.

After IUD Insertion

In the hours or days following insertion, you may experience minor side effects such as:

  • Light cramping or pelvic pain

  • Backache

  • Mild dizziness

  • Light spotting

pain relief and recovery
Over-the-counter pain relievers like ibuprofen can ease discomfort. These symptoms usually subside within a few days.

Contact your healthcare provider immediately if you experience:

  • Severe pain or persistent cramps

  • Heavy bleeding

  • Fever or flu-like symptoms

  • Unusual vaginal discharge

follow-up appointments
Most providers schedule a check-up within 2–4 weeks to ensure the IUD is in place. They’ll also show you how to check your IUD strings periodically.

When The IUD Starts Working

copper IUDs provide immediate protection from pregnancy once inserted.

hormonal IUDs, however, take about seven days to reach full effectiveness. During this time, you’ll need to use a backup birth control method such as condoms.

Once effective, your IUD protects you continuously for years—until you choose to remove it or it reaches the end of its approved lifespan.

The Bottom Line

IUDs are one of the safest, most effective, and most convenient forms of long-term birth control. Whether you choose a hormonal or copper IUD, both offer years of worry-free protection with minimal upkeep.

Because IUDs are reversible, you can have them removed at any time if your reproductive goals change.

If you’re considering an IUD, talk to your healthcare provider about which type aligns best with your lifestyle, preferences, and medical history. With professional guidance, an IUD can give you the confidence and peace of mind that comes with dependable contraception.