A New Study Links The Pill & IUDs With Breast Cancer Risk, But Don’t Freak Out Yet

On Dec. 6, a new study was released that said women who used hormonal birth control, such as the pill or an IUD, may have an increased risk of developing breast cancer. Although the increased risk is small, researchers noted, it was still statistically significant. Don't freak out just yet, though; doctors say this doesn't mean you should stop using your method of birth control.

The study, which was published in The New England Journal of Medicine, followed 1.8 million Danish women for more than a decade, and found that for every 100,000 women using hormonal birth control in the form of the pill or an IUD, there were 68 cases of breast cancer annually. There were 55 cases of breast cancer a year among women who didn’t use birth control. The rates of breast cancer were the same despite the type of contraception a woman used, though researchers noted it did vary by age and formulation.

However, there are other things to take into consideration when considering your birth control options, experts say. "When taking care of patients, it is important to take thorough history and weigh the risks and protective factors for every woman and ultimately let them decide what is the best method of birth control for them at that time," Dr. Tracey Wilkinson, pediatrics researcher at Indiana University School of Medicine in Indianapolis and a fellow with Physicians for Reproductive Health, tells Bustle. "This study showed an association between using hormonal birth control and breast cancer — but there are a lot of factors to consider when you are talking about breast cancer risks that are not a part of this study. Furthermore, the repercussions of an unplanned pregnancy are also really important to remember as well as the cancer protection you do get from hormonal birth control (such as decreased rates of uterine and ovarian cancer)."

The study also found a correlation between breast cancer risk and the amount of time a woman uses birth control. Women who used hormonal birth control for less than one year did not have an increased risk of breast cancer; while women who used birth control for more than 10 years had a 38 percent increase in their relative risk of developing breast cancer. This was consistent with a 1996 meta-analysis of over 50 studies about the link between breast cancer and birth control. However, Cancer.gov notes that the 1996 study found that "breast cancers diagnosed in women who had stopped using oral contraceptives for 10 or more years were less advanced than breast cancers diagnosed in women who had never used oral contraceptives."

“We did actually expect we would find a smaller increase in risk because today we have lower doses of estrogen in the hormone contraceptives, so it was surprising that we found this association,” Lina S. Mørch, a senior researcher at the University of Copenhagen and the paper’s lead author, was quoted in The New York Times. The authors suggested that the hormone progestin may also be responsible for the increase in risk.

Although the study does have public health implications, there were limitations to it, and more studies need to be conducted in order to more thoroughly understand the link between breast cancer and birth control. Study authors acknowledged in the report that “they could not take into account factors like physical activity, breastfeeding, and alcohol consumption, which may also influence breast cancer risk.”

It's also worth noting that despite the possibility of a small but statistically significant increase in risk of breast cancer, many people take birth control to mitigate other health concerns. Hormonal birth control is known to actually reduce the risk of some other cancers, including ovarian, endometrial, and colorectal cancer. It can also help control endometriosis, in addition to PMS and PMDD symptoms, including period pain. On top of all that, hormonal birth control is still one of the safest and most effective methods of preventing unintended pregnancy.

While there are other contraception options beside the pill and an IUD, and some varieties of IUDs that are hormone-free, the study didn’t find that any modern medical birth control methods were 100 percent risk-free. That’s why it’s important to have an ongoing conversation with your doctor about birth control, and go to your OB-GYN for your annual check up — even if you've been using your same method of birth control for years.

"Overall, hormonal birth control is incredibly safe. What is important that in any decision around birth control, [patients] are counseled on all forms and given the risks and benefits of each before they decide which birth control to use. Furthermore, making sure that all women have access to all forms of birth control, regardless of cost, is something that we as physicians and policy makers need to assure is possible for every person — regardless of their age, race or income," says Dr. Wilkinson.

While the results of this study might seem alarming at first to the millions of women who are currently taking or have taken birth control in the past, making hasty medical decisions is not advised. Talking to a medical professional and evaluating your health needs with your doctor as an ongoing process remains the best course of action when it comes to birth control options.