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Birth Control and Cancer: Is There a Link?

Hormonal contraception, including birth control pills, has been a popular form of birth control since it was first introduced in the 1960s. But some research, including a recent 2017 study, points towards a potential link between birth control and breast cancer.

Read on to get a better understanding of birth control’s role in your risk for breast cancer and what the risks and benefits are.  

Recent studies have shown that there may be a correlation between hormonal birth control and breast cancer. According to a study published in 2017 by the New England Journal of Medicine, hormonal contraception is correlated with a slightly increased risk of developing breast cancer.

However, this does not necessarily mean you should stop using it, according to experts. 

The important thing to remember is that this study showed the risk to be very, very small. If you stopped using birth control years ago, your risk of breast cancer is likely nearly the same as a woman who never used hormonal contraception at all.

But if you’re over the age of 40 and/or have an elevated risk of breast cancer, you can ask your doctor about non-hormonal options, such as a barrier method (e.g., condoms) or a non-hormonal intrauterine device (IUD). These findings are an opportunity to consider which form of birth control is best for you, weighing the potential risks, side effects, and benefits. 

There are also some details about these studies to keep in mind. Most studies that have looked at birth control and breast cancer have produced conflicting results. This may be related to the different levels of hormones present in birth control, which have changed over time.

In the 1960s, when oral contraceptives were first introduced, the levels of estrogen and progestin hormones were much higher than they are today. This could account for some of the earlier findings. Today, lower hormonal levels mean a lower risk. 

Most of the research done on birth control pills and breast cancer have been observational studies that can’t definitively prove that there is a relationship between birth control and cancer. This is because these kinds of studies do not take into account any differences between the women being studied, such as lifestyle, diet, environmental exposure, or other risk factors.

Some studies have found that the risk of cervical cancer is higher for women using oral contraceptives. Other studies have found that the risk for developing ovarian, endometrial, and colorectal cancer is reduced for women who take oral contraceptives.

One analysis, which looked at studies of more than 150,000 female participants, found that women who had ever used oral contraceptives had a 7 percent increased risk for developing breast cancer compared to women who did not use oral contraceptives. Those currently using oral contraceptives demonstrated a 24 percent increased risk. Researchers also found that this risk declined after the women stopped taking oral contraceptives, and that after 10 years had no increased risk compared to women who had never taken them.

An increased risk of cervical cancer was found among women who had used oral contraceptives for five years or longer compared to those who had never used them. There is also a correlation between the length of time an oral contraceptive is taken and the risk: the longer the use, the greater the risk. One study found that the risk increased 10 percent with less than 5 years of use, 60 percent with 5 to 9 years of use, and doubled with more than 10 years of use. The increased risk decreased over time after women stopped taking oral contraceptives.    

In the case of endometrial cancer, risk actually decreases for women who have taken oral contraceptives compared to those who have not. Risk for endometrial cancer is decreased by at least 30 percent, and the longer a woman takes oral contraceptives, the lower her risk will be. This protective effect continues for many years even after stopping birth control. In one study, this impact was particularly noticeable in women who were smokers and maintained sedentary lifestyles. 

Birth control has been shown to lower the risk of ovarian cancer. In other words, your chances of developing ovarian cancer are lower if you have taken birth control than if you haven’t. The longer you take oral contraceptives, the lower your risk becomes, and the protection continues for up to 30 years after stopping. 

Your chances of developing ovarian cancer are lower if you have taken birth control than if you haven’t.

Naturally occurring estrogen and progesterone can stimulate some cancer development. Because hormonal birth control contains synthetic versions of estrogen and progesterone,  these forms of birth control may increase cancer risk. They may also increase the risk of cervical cancer by making cells in the cervix more susceptible to infection from high-risk human papilloma viruses.   

Since some studies have shown a correlation between oral contraceptives and breast cancer, what is the safest form of birth control? First, it’s important to weigh the risks and benefits. Birth control is extremely important in preventing unwanted pregnancies. Unplanned or unwanted pregnancy can involve emotional stress and the possible need for medications and surgery, all of which can be prevented by taking birth control in a safe, responsible manner. 

Birth control may also have a protective quality. For both ovarian and endometrial cancers, birth control pills may offer protection, lowering the risk the longer you take them. And even after stopping, the protection against these cancers can continue. 

Most doctors agree that age is a factor to consider when choosing birth control. Since less than 5 percent of women diagnosed with breast cancer in the United States are younger than 40, younger women in their teens, 20s, and 30s are at a much lower risk. The risk increases over time for all cancer types, as cells age and become more susceptible to developing abnormalities. For this reason, doctors recommend reevaluating your birth control methods when you turn 40. 

You can also consider using non-hormonal birth control methods, such as condoms and copper IUDs

Keep in mind that there are a number of other lifestyle choices within your control that can influence breast cancer risk. Obesity and alcohol use have been linked to breast cancer, so making exercise a part of your life and watching your alcohol intake can be part of a proactive approach to staying healthy.   

Like with any medication, your decision about birth control is individual and personal. Learning the risks and benefits is a good place to start. Having a conversation with your doctor, who can tell you about each birth control option in more depth, is also a smart decision.

https://www.cancer.gov/about-cancer/causes-prevention/risk/hormones/oral-contraceptives-fact-sheet

https://www.breastcancer.org/research-news/do-hormonal-contraceptives-increase-risk

https://www.health.harvard.edu/womens-health/study-finds-weak-link-between-birth-control-and-breast-cancer

https://www.ncbi.nlm.nih.gov/books/NBK234348/

https://www.health.harvard.edu/womens-health/study-finds-weak-link-between-birth-control-and-breast-cancer

https://www.cancer.gov/about-cancer/causes-prevention/risk/hormones/oral-contraceptives-fact-sheet

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