The International Agency for Research on Cancer (IARC) has classified combined oral contraceptives (COCs) as a Group 1 carcinogen, meaning that there is sufficient evidence that they can cause cancer in humans. This classification is based on studies that have shown that COCs can increase the risk of breast and cervical cancer. However, they can also decrease the risk of ovarian, uterine, and colorectal cancer.
How does birth control affect cancer risk?
The exact mechanisms by which birth control affects cancer risk are not fully understood. However, it is thought that the hormones in COCs can stimulate the growth of breast cells and cervical cells. This can increase the risk of developing these types of cancer. COCs can also decrease the risk of ovarian cancer by decreasing the number of times a woman ovulates. This is because ovulation can damage the lining of the ovaries, which can increase the risk of cancer. COCs can also decrease the risk of uterine and colorectal cancer by thinning the lining of the uterus and decreasing the amount of bile acid in the bloodstream.
Studies on the link between birth control and cancer
There have been many studies that have looked at the link between birth control and cancer. Some of the most important studies include:
- The Million Women Study, which was a large study of British women that found that COC use was associated with an increased risk of breast cancer.
- The Nurses' Health Study, which was a large study of American nurses that found that COC use was associated with an increased risk of cervical cancer.
- The Danish Breast Cancer Cooperative Group Study, which found that COC use was associated with an increased risk of breast cancer in younger women.
- The Women's Health Initiative, which found that COC use was associated with an increased risk of breast cancer after 5 years of use.
Your individual cancer risk depends on a number of factors, including your age, family history, and lifestyle. We advise speaking a knowledgeable endocrinologist, such as our team of experienced doctors at Holtorf Medical Group that provide individualized care.
Are there alternatives to birth control?
Yes, the safest birth control methods that do not disrupt your hormone health include:
- Fertility awareness methods (FAMs): FAMs allow women to track their fertility using a variety of evidence-based techniques.
- Barrier methods: Barrier methods, such as condoms and diaphragms, prevent sperm from reaching the egg.
Which birth control method is right for you?
The best birth control method for you depends on your individual needs and preferences. It is important to talk to your doctor about your options and to choose a method that is right for you.
Conclusion
The IARC's classification of COCs as a Group 1 carcinogen is a reminder that any medication, including birth control, can have potential risks. It is important to talk to your doctor about your individual cancer risk and to choose a birth control method that is right for you.
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