If you have taken or are considering taking birth control pills, you may wonder whether they can impact your risk for cancer. Because birth control pills contain the hormones estrogen and progesterone and some cancers rely on these hormones to grow, some people may worry that taking a pill with these hormones can increase their risk of developing cancer.
Here, learn what scientific research says about how taking birth control pills can affect your risk for breast cancer, ovarian cancer, and uterine cancer, and what questions you should ask your health care team when taking or considering taking oral contraceptives.
How do birth control pills work?
Birth control pills, also called oral contraceptives or “the pill,” are a popular form of contraception. From 2017 to 2019, 14% of women ages 15 to 49 in the United States used oral contraceptives, according to the U.S. Centers for Disease Control and Prevention. Additionally, 16% of women in the same age group worldwide were using oral contraceptives in 2019, according to the United Nations.
Most birth control pills contain synthetic versions of the hormones progesterone and estrogen. When a pill contains both hormones, it is called a “combined oral contraceptive.” The “mini pill” is a type of birth control pill that contains only synthetic progesterone, called progestin. The hormones in the pill work by preventing the body from ovulating or releasing an egg. They also change the lining of the uterus and cervical mucus. Together, this prevents sperm from fertilizing an egg during intercourse. Birth control pills are taken at the same time every day, and they prevent pregnancy 99% of the time, when taken correctly.
Oral contraceptives have changed significantly since the 1960s, when they were first approved by the U.S. Food and Drug Administration. They now contain lower concentrations of estrogen and progestin, but they are just as effective and safe in preventing pregnancy. However, all medications, including oral contraceptives, can carry certain risks.
How does taking birth control affect my risk for cancer?
Overall, research has shown that taking the pill can decrease your risk for ovarian and uterine cancers, but the effect on breast cancer risk is not clear. However, how much birth control influences your cancer risk is still being studied.
How the birth control pill impacts your risk of ovarian cancer
Nearly 20,000 people will be diagnosed with ovarian cancer in the United States this year. Taking the pill has been found to reduce the risk of ovarian cancer by 30% to 50%, according to several studies. Additionally, studies on lower-dose pill formulations, like a 2000 study in the American Journal of Epidemiology, found that taking the pill reduced the risk of ovarian cancer by 40% compared to people who had never taken the pill. Birth control pills can also help protect people with a family history of ovarian cancer and those who have genetic mutations linked to hereditary ovarian cancer, such as BRCA1 and BRCA2.
How the birth control pill impacts your risk of uterine cancer
About 66,000 people will be diagnosed with uterine cancer this year. Taking the pill has been found to reduce the risk for uterine cancer, and those protections are strengthened the longer the pill is taken. A 2018 study in JAMA Oncology reported that taking the pill reduced the risk for uterine cancer by 34%. People who smoked, were overweight, and who rarely exercised were found to have even more benefit from taking the pill.
“Many women have concerns about long-term risks associated with taking birth control pills. The good news is that taking oral contraceptives has been associated with a decreased risk of some cancers, including ovarian and uterine cancers. It’s always important to discuss with your doctor what birth control strategy is right for you, however, based on your own personal risk factors.” – Merry Jennifer Markham, MD, FACP, FASCO, Chief of the Division of Hematology and Oncology and clinical professor in the Department of Medicine at the University of Florida and the 2022 Cancer.Net Associate Editor for Gynecologic Cancers
How the birth control pill impacts your risk of breast cancer
Breast cancer is the most common cancer diagnosed in women in the United States, besides skin cancer. Research on the risk of breast cancer from the pill is extensive, but results from these studies have not come to the same conclusions. Some studies show no risk, others show very small risk, and others show small but significant risk.
“Studies of breast cancer risk among women who receive hormonal contraceptives show inconsistent findings–-from no elevation in risk to a 20 to 30% increase in risk,” wrote authors of a 2017 Danish study in the New England Journal of Medicine, referencing 18 studies over 14 years. In their study, the Danish researchers found the risk of breast cancer was 20% higher among women who currently or recently used combined oral contraceptives, and the risk increased with duration of use.
On the other hand, a large 2002 study published in the New England Journal of Medicine found no significant increased risk of breast cancer among women ages 35 to 64 who were currently taking or had ever taken the pill. Research in this area is ongoing. It is best to talk with your health care team about how taking birth control pills may impact your risk for breast cancer.
Questions to ask your health care team about the pill and your personal cancer risk
All medications, including oral contraceptives, can carry risks, so it’s important to talk with your health care team about the best birth control option for you. Together, you can take into account factors like your lifestyle, overall health, cancer history, budget, age, and short- and long-term goals in preventing pregnancy or starting a family.
“Although birth control pills are an important treatment option for many premenopausal women, for some, the risks may outweigh the benefits. Discuss your personal and family medical history with your doctor to determine if birth control pills are an appropriate option for you.” – Norah Lynn Henry, MD, PhD, FASCO, professor and Interim Chief of the University of Michigan's Division of Hematology/Oncology in the Department of Internal Medicine and the 2022 Cancer.Net Associate Editor for Breast Cancer
Here are some questions you can ask your health care provider to start the conversation around birth control pills and your personal cancer risk:
What are the risks for cancer with this birth control, if any?
What are the protections from cancer with this birth control, if any?
What other benefits or harms could this contraceptive have?
Are there other contraceptives that pose fewer risks or greater benefits?
How does my family history or genetics affect which type of contraceptive I should choose?
Does my personal history or treatment for cancer affect which contraceptive I should choose?
What should I know about recent studies researching oral contraceptives and cancer risk?
Do the benefits of using birth control pills outweigh the risks, based on my age and health history?