These types of birth control raise risk of breast cancer: Oxford study finds

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Hormonal contraceptives slightly increase women's risk of breast cancer, according to a study conducted by researchers at the University of Oxford. 

The study, recently published in the journal PLOS Medicine, gathered data from nearly 10,000 women between the ages of 20 and 49, who were diagnosed with invasive breast cancer between 1996 and 2017 in the U.K. Researchers also collected data from just over 18,000 women who did not have breast cancer. 

According to the study's abstract, "findings suggest that there is a relative increase of around 20% to 30% in breast cancer risk associated with current or recent use of either combined (estrogen+progestagen) oral or progestagen-only contraceptives."

It adds: "Use of progestagen-only hormonal contraceptives has increased substantially over the last decade, and in 2020, there were almost as many prescriptions in England for oral progestagen-only contraceptives as for combined oral contraceptives. Given the increasing use of progestagen-only contraceptives, it is important to understand how their use is associated with breast cancer risk."

Data used in the study was obtained from the Clinical Practice Research Datalink (CPRD). The CPRD results were combined with data from previous studies, which included women from a wider age range. 

As a result of combining the studies, researchers found that the resulting 15-year absolute “excess risk” associated with five years' use of oral combined or progestagen-only contraceptives in high-income countries was estimated at eight per 100,000 users from age 16 to 20. For women ages 35 to 39, the excess risk was 265 per 100,000 users, according to the study. 

“On average, 44% of women with breast cancer and 39% of matched controls had a hormonal contraceptive prescription, with about half the prescriptions being for progestagen-only preparations,” the study adds.

According to the study's authors, these “excess risks must be viewed in the context of the well-established benefits of contraceptive use in women’s reproductive years.” 

Dr. Angela Lanfranchi, who co-founded the Breast Cancer Prevention Institute, contended that studies like this one aren't offering any new information, telling The Christian Post on Thursday that such studies "increase" what has already been found. Lanfranchi provided CP with a copy of a CitizenGo petition on hormonal contraceptives which also concluded that certain types of birth control can elevate a woman's risk for breast cancer. 

In addition to the petition, a 2017 study that followed 1.8 million Danish women for about 10 years concluded that for every 100,000 women on hormonal birth control, there are 68 annual cases of breast cancer. 

According to the American College of Obstetricians and Gynecologists, in addition to using them for birth control, some women take progesterone-only contraceptives for heavy or painful periods. Changes in bleeding are a common side effect, according to the ACOG, with some women’s periods stopping completely after using this form of contraception. 

The researchers also acknowledged some of the study’s limitations, including a lack of information on a woman’s prescription history, preventing the authors from assessing the long-term associations of contraceptive use on breast cancer risks. Still, the researchers do not believe that this limitation impacted their ability to analyze short-term associations.

The researchers noted that the information on family history of breast cancer in their study was “relatively incomplete,” noting that this information was typically recorded around the time of a breast cancer diagnosis. 

“While it is unclear what effect, if any, adjustment for family history of breast cancer would have made to our findings, previously published findings for combined oral contraceptives were unaltered after adjustment for family history, and two studies of progestagen-only contraceptives included in our meta-analysis found little change in associated risks after adjustment for a number of additional factors including family history,” the study added. 

Discussing the risks of contraception highlighted by the study, Claire Knight of Cancer Research U.K. stated that these risks were small and should not discourage women from using birth control. 

“Women who are most likely to be using contraception are under the age of 50, where the risk of breast cancer is even lower,” she told The Guardian last week. “For anyone looking to lower their cancer risk, not smoking, eating a healthy balanced diet, drinking less alcohol, and keeping a healthy weight will have the most impact.”

“There are lots of possible benefits to using contraception, as well as other risks not related to cancer,” she continued. “That’s why deciding to take them is a personal choice and should be done after speaking to your doctor so you can make a decision that is right for you.”

As The Christian Post reported in November, the U.S. Food and Drug Administration indefinitely postponed a meeting to review an application for an over-the-counter birth control pill. The application review happened amid debates about over-the-counter birth control and access to abortion-inducing drugs following the Supreme Court’s reversal of Roe v. Wade

The FDA confirmed in September that it scheduled a meeting with external experts on Nov. 18, 2022, to review pharmaceutical company Perrigo's application for an over-the-counter birth control pill known as Opill. 

The pill is a non-estrogen contraceptive that has required a prescription since it was first approved in 1973. In a November statement to CP, an FDA spokesperson said the meeting’s postponement did not indicate whether it had made a decision regarding the approval of the application.

Samantha Kamman is a reporter for The Christian Post. She can be reached at: Follow her on Twitter: @Samantha_Kamman

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