The short answer
A hormonal IUD is a small device placed in the uterus that slowly releases the hormone levonorgestrel. Studies summarized by the National Cancer Institute link its use with a lower rate of cancer of the uterine lining. The same summary reports no increased breast cancer risk in the evidence it reviewed.
A hormonal IUD is a levonorgestrel-releasing intrauterine system (LNG-IUS).
NCI's prevention summary reports that women who had ever used a hormone-releasing IUD had lower rates of endometrial cancer than never-users (Norwegian study, relative risk 0.22).
The same devices are used as a treatment for endometrial hyperplasia, an overgrowth of the uterine lining that can sometimes come before cancer.
Evidence cited in that summary found no increased risk of breast cancer with these devices.
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The whole article, with every detail and caution.
The short answer
This page is for anyone using, or thinking about, a hormonal IUD who wonders about cancer risk.
A hormone-releasing IUD is linked with less cancer of the uterine lining (endometrial cancer), not more. That is the direction the evidence points in the National Cancer Institute's prevention summary for endometrial cancer.
That summary is written for clinicians, so it is dense. Here is what it actually says, in plain words.
What the device is
An IUD is a small T-shaped device. A clinician places it inside the uterus. The hormonal type releases a slow, steady trickle of levonorgestrel. That is a progestin hormone. Doctors sometimes call it a levonorgestrel-releasing intrauterine system, or LNG-IUS for short.
What the research found about the uterine lining
The NCI summary cites two population studies.
- In a Norwegian study, the relative risk of endometrial cancer among women who had ever used a hormone-releasing IUD was 0.22 compared with never-users. A number below 1 means fewer cases in the users.
- In a Finnish study, after at least one purchase of the device, 37 endometrial cancers were observed where 80 would have been expected.
Both point the same way. Users had fewer cancers of the uterine lining than you would otherwise expect to see.
NCI reports that use of the device is linked with a statistically significant lower risk of endometrial cancer.
Why that fits with how the device is used in clinics
The same summary makes another point. The hormone-releasing intrauterine system is an effective treatment for endometrial hyperplasia. That is an overgrowth of the lining. In some cases it is a step on the road toward cancer. The device is also used for early-stage, low-risk endometrial cancer.
What about breast cancer
People ask this most often, because the device holds a hormone. The NCI summary reports that use of a levonorgestrel-releasing intrauterine system was associated with no increased risk of breast cancer in the evidence it reviewed.
That is what the source says.
How to hold this information
A few honest limits are worth naming.
Population studies compare large groups. They show what tends to happen across groups of women. They do not forecast what will happen to you. No contraceptive choice can.
An IUD is not a cancer screening test. Screening is a separate track with its own schedule. Ask your care team what applies to you.
If you are deciding
Contraception decisions rest on many things at once. How heavy your periods are. Whether you want something you do not have to think about daily. Other health conditions. Cost and access. Cancer risk is one input among several. On the endometrial side, the NCI evidence points toward lower risk.
Bring your own history to the conversation. Say if you have a family history of uterine cancer. Say if you have had abnormal findings in the lining before. That is a different starting point, and the clinician who knows your chart is the person to sort it out.
If you already have one
Ask your clinician before making any change to your device. The evidence here points toward fewer cancers of the uterine lining among users.
Ask your clinician when yours is due for replacement. Tell them about any bleeding that is new or clearly changed.
Sources
National Cancer Institute, Endometrial Cancer Prevention (PDQ), health professional version, checked 2026-10-02.
Common questions
Is a hormonal IUD safer than the pill when it comes to cancer?
They are different products and NCI covers them in separate summaries, so a head-to-head ranking is not something the source supports. What the endometrial prevention summary does say is that ever-users of a hormone-releasing IUD had lower endometrial cancer rates than never-users.
Does a hormonal IUD cause breast cancer?
The NCI summary reports that use of a levonorgestrel-releasing intrauterine system was associated with no increased risk of breast cancer in the evidence reviewed. If breast cancer risk is on your mind, bring your personal and family history to your clinician.
Can an IUD be used to treat a problem in the uterine lining?
Yes. NCI describes the hormone-releasing intrauterine system as an effective treatment for endometrial hyperplasia and for early-stage, low-risk endometrial cancer. That use is a decision made with a gynecologist, not something you arrange yourself.
Does having an IUD mean I can skip cervical screening?
No. An IUD sits in the uterus and does nothing about the cervix. Cervical screening follows its own schedule, and your clinician can tell you where you are in it.
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Plain-language explanation of the published sources cited on this page. AI-assisted, source-checked, not clinician-reviewed.
Sources last checked: 2026-10-02 what this meansLast updated: 2026-10-02Next planned review: 2027-08-11
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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