Can an IUD cause cancer? Separating medical myths from your actual health risks

So, you're scrolling through TikTok or some health forum and you see a terrifying headline. Someone claims their birth control ruined their life. Or worse, you’re sitting in the doctor's office, staring at that tiny plastic "T" and wondering: Can an IUD cause cancer? It’s a heavy question. It’s also one that doctors hear constantly because, honestly, the internet is a chaotic place for medical advice.

The short answer is no. But also, it’s a bit more complex than a simple "yes" or "no" because the type of IUD you choose actually changes how it interacts with your body's cells.

The big question: Can an IUD cause cancer?

Let’s get the anxiety out of the way first. Research from major institutions like the American Cancer Society and the Mayo Clinic generally shows that IUDs don't cause cancer. In fact, for many women, they actually do the exact opposite. They act like a tiny, plastic shield against certain types of reproductive cancers.

We’re talking about a device that sits in your uterus for years. It makes sense to be skeptical. But the data we have—decades of it—suggests that intrauterine devices are among the safest long-term options we have.

Why people get scared of the Mirena or Kyleena

Most of the fear usually centers around hormonal IUDs. These brands (Mirena, Liletta, Kyleena, Skyla) release a progestin called levonorgestrel. Since some breast cancers are hormone-sensitive, people naturally freak out. They think, "If I’m putting hormones in my body, am I fueling a fire?"

It’s a fair thought.

However, the amount of hormone released by an IUD is localized. It’s tiny. Compared to the pill, which travels through your entire bloodstream, the IUD is mostly just doing its thing right there in the uterine lining.

The surprising link between IUDs and cancer prevention

Here is the part that usually shocks people. While you’re worried about whether an IUD can cause cancer, your IUD might actually be lowering your risk of getting it.

Specifically, we’re talking about endometrial cancer and cervical cancer.

💡 You might also like: Can DayQuil Be Taken At Night: What Happens If You Skip NyQuil

1. Endometrial Protection: The hormonal IUD thins out the lining of your uterus. This is why many people stop having periods altogether. By keeping that lining thin, the IUD prevents the "overgrowth" of cells (hyperplasia) that can eventually turn into cancer. For some women with early-stage endometrial changes, doctors actually prescribe a hormonal IUD as a form of treatment.

2. Cervical Cancer: This one is wild. A massive meta-analysis published in Obstetrics & Gynecology looked at data from thousands of women. They found that IUD users had a roughly 30% lower risk of developing cervical cancer.

Why? Scientists aren't 100% sure yet. Some think the act of inserting the IUD triggers an immune response in the cervix that helps the body fight off HPV (Human Papillomavirus). Others think that when the IUD is removed, it might scrape away precancerous cells. Whatever the mechanism, the protective effect is real.

What about breast cancer?

This is where the nuance lives. This is the "gray area" that makes people nervous.

A few years ago, a study out of Denmark made waves because it suggested a slightly higher risk of breast cancer in women using hormonal contraceptives, including the IUD. The increase was small—we’re talking about one extra case of breast cancer for every 7,690 users.

But context matters.

If you already have a high genetic risk for breast cancer, or if you are a breast cancer survivor, your oncologist will probably tell you to skip the hormonal IUD. For the general population, though, most experts agree the benefits of pregnancy prevention and the reduction in uterine cancer risk outweigh this very slight statistical "blip" in breast cancer data.

Copper IUDs: The non-hormonal alternative

If the word "hormone" makes you lose sleep, there's always the Paragard. It’s just copper and plastic. No hormones. No mess.

📖 Related: Nuts Are Keto Friendly (Usually), But These 3 Mistakes Will Kick You Out Of Ketosis

Copper IUDs don't have the same link to breast cancer concerns because they don't mess with your endocrine system. They work by creating an inflammatory environment that is toxic to sperm. It sounds aggressive, but it’s localized and highly effective. Interestingly, copper IUDs also show a protective effect against cervical cancer.

Inflammation and the "foreign body" theory

Some people worry that because an IUD causes a "low-grade inflammation" in the uterus, it could lead to cellular damage over time. Chronic inflammation is often linked to cancer in other parts of the body—think of how acid reflux can lead to esophageal cancer.

But the uterus is different.

The inflammation caused by a copper IUD is specific to the uterine fluid and the lining. It’s not the kind of systemic, raging inflammation that typically triggers oncogenesis (the birth of cancer). In fact, the way the IUD changes the local immune environment seems to be exactly why it helps protect the cervix.

Real talk about IUD complications

Look, I’m not saying IUDs are perfect. They aren't. They can cause:

• Perforation (the IUD poking through the uterine wall—very rare, but scary).
• Expulsion (your body literally birthing the device because it doesn't want it there).
• PID (Pelvic Inflammatory Disease), usually if you have an undiagnosed STI at the time of insertion.

But none of these things are cancer.

If you feel a sharp pain, or if you can't find your strings, you need to see a doctor. But you don't need to assume your cells are mutating.

How to manage your risk

If you are still spiraling about can an IUD cause cancer, here is the practical roadmap for staying safe.

👉 See also: That Time a Doctor With Measles Treating Kids Sparked a Massive Health Crisis

Know your family tree. If your mom, sister, or grandmother had breast cancer, tell your doctor. This is the single most important piece of information they need to help you choose between a hormonal IUD, a copper IUD, or something else entirely.

Don't skip your paps. The IUD protects the cervix, but it isn't a magic shield. You still need regular screenings to check for HPV and abnormal cells. The IUD makes it less likely you'll have issues, but it doesn't make it impossible.

Listen to your flow. If you have a hormonal IUD and your periods stop, that’s usually fine. But if you have "breakthrough bleeding" that is heavy, painful, or just feels off after years of no periods, get an ultrasound. It’s probably just the IUD shifting or the lining getting a bit thin, but it's always worth checking.

Actionable steps for your next appointment

Don't just walk in and let them "up-sell" you on a brand. Go in with a plan.

• Ask for a "nulliparous" IUD if you've never given birth. These are slightly smaller (like Kyleena or Skyla) and can be more comfortable.
• Discuss the copper vs. hormonal trade-off. If you have heavy, painful periods naturally, the copper IUD might make them worse. If you have a history of depression, some people find hormonal IUDs affect their mood.
• Request a string check. Have your doctor show you how to feel for the strings yourself so you can monitor the device at home.

The bottom line? The fear that an IUD can cause cancer is largely unsupported by modern science. For the vast majority of people, these devices are a "set it and forget it" miracle that actually provides a significant layer of protection against some of the most common reproductive cancers.

Check your strings. Keep your appointments. Breathe easy.

References and Further Reading:

1. American College of Obstetricians and Gynecologists (ACOG): Long-Acting Reversible Contraception (LARC) Practice Bulletin.
2. The Lancet Oncology: Study on progestogen-only contraceptives and breast cancer risk (2023 update).
3. International Journal of Cancer: Meta-analysis on IUD use and risk of endometrial cancer.
4. National Cancer Institute (NCI): Fact sheets on Oral Contraceptives and Cancer Risk (including IUD data).