Many forms of contraception have more than one use. For example, oral contraceptives can regulate your menstrual cycle, and condoms can prevent sexually transmitted diseases. According to new research, an intrauterine device (IUD) might also be beneficial in multiple ways.
A recent meta-analysis published in the journal Obstetrics & Gynecology looked at observational studies of more than 12,000 people. Researchers found that cervical cancer is about one-third less frequent in those who have used an IUD.
The study’s author, Victoria Cortessis, PhD, of the Keck School of Medicine at the University of Southern California, declared that the findings were significant. “The possibility that a woman could experience some help with cancer control at the same time she is making contraception decisions could potentially be very, very impactful,” Cortessis said in a press release.
Since this is relatively new research, we don’t yet know enough about how and why there is a link between cancer prevention and IUDs. It’s also unclear how long someone would have to use an IUD before it has a cancer-fighting effect.
The study is also limited because we don’t know whether the subjects used hormonal or non-hormonal IUDs. That said, Cortessis told TIME that most of the studies probably involved non-hormonal IUDs, given the time periods and the nature of the studies they analyzed.
How do IUDs work?
Even without their potential cancer-fighting benefits, IUDs are an effective contraceptive with multiple benefits.
An IUD is a small, T-shaped device. It’s inserted into your uterus by a trained medical practitioner, and it can stay there for three to 10 years, depending on the type. If you decide you want to conceive or if you change your mind about wanting an IUD, you can have it removed—it’s totally reversible.
There are two kinds of IUDs: hormonal and non-hormonal. Hormonal IUDs, like the Mirena and Skyla IUDs, consistently release a small amount of hormones. This thickens the mucus of the uterus to prevent sperm from meeting the egg. It also thins the uterine wall to prevent a fertilized egg from implanting itself in the uterus. Hormonal IUDs might also make your period lighter and shorter.
The non-hormonal kind contains a small amount of copper and can usually remain in your uterus for up to 10 years. It’s a useful form of contraception for those who don’t want to use hormonal contraception but aren’t fans of barrier methods such as condoms. A potential downside of the non-hormonal IUD? It might cause longer, heavier, or more painful periods.
Current research suggests that nearly anyone can use an IUD, including those who have never given birth. The American Congress of Obstetricians and Gynecologists has advocated that both adolescents and adults can benefit from IUDs.
According to the World Health Organization (WHO), both the copper and the hormonal IUD are over 99 percent effective as a form of birth control—making them one of the most reliable forms of contraception.
Part of the reason IUDs are so effective is that they’re easy to use: Once inserted, you don’t have to worry about it. A condom is only effective if you use it properly, and oral contraception is only effective if you take it consistently. The IUD doesn’t depend on your memory to work.
How could an IUD prevent cervical cancer?
Although the study suggested there’s a link between IUDs and cervical cancer prevention, it doesn’t tell us why the link exists.
What we do know is that cervical cancer is commonly caused by human papillomavirus (HPV). According to WHO, two types of HPV are responsible for 70 percent of cervical cancer cases.
According to Cortessis, there are a few different ideas about how the IUD could prevent cancer. One theory is that the IUD, being a foreign object, causes the immune system to focus on the reproductive organs. When an infection like HPV enters the body, the immune system is able to successfully fight it off before it causes cancer.
Cortessis has suggested that gynecologists shouldn’t start recommending IUDs solely to prevent cervical cancer, though. For now, we know for sure that the best way to prevent cervical cancer is to prevent HPV. This includes having the HPV vaccine if you’re able to do so. Regular Pap smears can also detect abnormal cells on the cervix, enabling you to intervene before the cancer develops.
Even so, the research provides hope for the future. WHO estimates that about 270,000 people died from cervical cancer in 2012 alone, and those numbers are expected to increase greatly. Most cervical cancer cases occur in low- and middle-income countries, where access to vaccines and screening can be challenging.
If IUDs are truly effective in preventing cancer, they might become another tool in the fight against cervical cancer—one that doesn’t require yearly checkups or potentially expensive vaccines.