Important News for Women Weighing Birth Control Options: New Research Finds IUDs Could Reduce Ovarian Cancer Risk as Much as 32%

The authors of the new study, which was just published in the journal Obstetrics & Gynecology this week, analyzed the results of 11 large studies from different parts of the world and found that, while the risk reduction ranged significantly (from 15-32 percent), the pattern was clear: “IUD use is associated with a reduced incidence of ovarian cancer.”

Ovarian cancer, which is estimated to take 14,000 lives this year alone, is a really difficult cancer to diagnose, in part because there is no one screening test available to detect it. Symptoms of ovarian cancer are tough to discern, too; bloating, constipation, and stomach pain are all easy to attribute to conditions other than cancer. Because of these symptom and screening difficulties, ovarian cancer is commonly diagnosed at a later stage, after it has spread beyond the ovaries, making it much more difficult to treat than it would be if it were diagnosed early on, when it is still locally confined to the ovaries.

RELATED: Ovarian Cancer: What Are The Symptoms And Warning Signs?

All of these factors make ovarian cancer a tough diagnosis–and, accordingly, prevention is often top-of-mind. Researchers have previously pointed to oral contraceptives as one way to cut the ovarian cancer risk. According to Dr. Jonathan Berek, Director of Stanford Women’s Cancer Center, if women have taken the birth control pill for up to five years and have had two children, they can reduce their risk of developing the most common type of ovarian cancer by as much as 70 percent. (If the two children part sounds confusing, it’s worth noting that Dr. Berek spoke about having children as another way to reduce ovarian cancer risk in addition to oral contraceptive use — which we can understand to mean in the years before or after pregnancy.)

RELATED: Can Birth Controls Pills Sharply Reduce Your Cancer Risk? New Study Finds The Pill Helps Reduce Risk Of Aggressive Ovarian Cancer

“Those are very important things to know,” Dr. Berek told SurvivorNet in a previous conversation about ovarian cancer risk reduction. “Those are two of the things that people actually can do if they’re able to have children and if they have a choice of what kind of birth control to use, then the oral contraceptive would be the contraceptive of choice to reduce the risk.”

Dr. Jonathan Berek spoke with SurvivorNet about ways to reduce ovarian cancer risk.

But preferences differ when it comes to contraceptives, and many women who choose contraceptives prefer options other than oral pills. One such option is the IUD — which has become increasingly effective and safe in the past decade. Now, IUDs are about 99 percent effective when it comes to preventing unwanted pregnancies, and complications are really rare.

RELATED: Be Aware, Be Pushy: After Losing His Wife To Ovarian Cancer, Doug Wendt Started A Foundation To Empower Women

How, Exactly, Does an IUD Prevent Ovarian Cancer?

The new study did not look into the actual mechanism (that is, way) that IUDs might work to reduce the risk of ovarian cancer. The authors say more research is needed to say for sure.

Having said that, the study’s authors, including Dr. Saketh Guntupalli and Dr. Lindsay Wheeler, both of the University of Colorado, offered some possibilities. One possibility had to do with the hormones in IUDs.

“Many types of IUDs have hormones in them and exhibit anti-estrogenic effects which may help women who are at high risk for ovarian and uterine cancers," Dr. Guntupalli said in a UCHealth news release about the study. "The second reason was that all the different kinds of IUDs…resulted in some local inflammatory effects. Immune cells increase and are thought to halt the threat of cancer."

Dr. Ritu Salani of the Ohio State University Wexner Medical Center spoke with SurvivorNet about how women with a high risk of ovarian cancer can reduce that risk. 

It’s worth noting that not all IUDs have hormones in them. IUDs work by blocking sperm from fertilizing the egg (an IUD is a small device shaped like a “T” that is inserted through the vagina and cervix into the uterus). The IUDs that have hormones in them (such as the popular Mirena, Skyla, Kyleena, and Liletta brands) release a hormone called levonorgestrel, which can alter the menstrual cycle in addition to thickening the cervical mucus to further prevent pregnancy. Non-hormonal IUDs, such as the Paragard, block fertilization by way of their copper coil, but do not release hormones.

The UC Health study did not differentiate the type of IUDs that the women in the 11 international studies used, meaning, again, that they could not say for sure that it was the hormones that had the ovarian cancer risk-reducing effect.

“More research is needed, both because they included such a broad array of women who had so many different kinds of IUDs, and because they couldn't determine if the women had IUDs for ’10 years or 10 months,'” Dr. Guntupalli said in the UCHealth news release.

RELATED: Study: Most Women Want to Address Their Sexual Health Before Cancer Treatment

Regardless, both Dr. Guntupalli and Dr. Wheeler said that the results of the study are “incredibly compelling” and should be factored into conversations that women have with their gynecologists about contraceptive choices and cancer risk.

“Given the grave nature of an advanced ovarian cancer diagnosis, even a modest increase in the use of IUDs may lead to a decrease in the incidence of ovarian cancer in a general population of women, leading to a significant population-level effect," the researchers wrote.

RELATED: Ovarian Cancer Prevention: Methods for High-Risks Patients

This could be especially true for women who know they have a high risk of developing ovarian cancer — including women with family histories or women who have tested positive for certain genetic mutations associated with ovarian cancer.

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