“This, I think, further supports the argument that there are risks associated with hormonal birth control,” Duane told CNA. “Cancer is just one of the risks. There is also a significant risk of blood clots that can lead to stroke and heart attack in women. And I will tell you, I have personally met families who have buried their daughters due to the side effects of hormonal birth control, who felt anger and frustration that they were never informed.”
Any evaluation of the elevated relative risk of breast cancer should be based on each woman’s “baseline risk,” according to Duane.
“I do not have a family history of breast cancer. So I have a lower baseline risk. I also breastfed my children for nearly 10 years. Breastfeeding is a known factor that reduces a woman's risk,” she said. “For example, I might have a risk of breast cancer of 1%, whereas a person who has a strong family history and who also smokes, which is a known risk factor for breast cancer, might have a 10% risk of breast cancer.”
A 30% risk increase for Duane might mean a risk of breast cancer rising from 1% to 1.3%, whereas another woman could see a risk increase from 10% to 13%.
While birth control proponents will argue that contraceptives are safer than pregnancy, Duane said that just because someone is not on birth control does not mean that she will be pregnant. Duane herself has been pregnant for 36 months out of 30 years in which she has not used birth control.
Kirstin Pirie, a researcher at the University of Oxford, was the lead author of the progestogen-only contraceptive study. She told CNN that excess risks must be seen in light of the “well-established benefits” of contraceptive use for women of reproductive age, including birth control and hormone regulation.
Duane objected to this description.
“Pregnancy is not a disease, and the purpose of birth control is to prevent pregnancy. So hormonal birth control is synthetic steroid hormones that are given to healthy women to essentially create a diseased state, to make them infertile,” she said. “It does not regulate hormones; to be very clear, it suppresses normal hormone production.”
“The World Health Organization [WHO] recognizes hormonal birth control, specifically combination hormonal birth control, as a class one carcinogen. It is in the same category of cancer risk as tobacco, and asbestos,” she said. “And yet, it is considered a preventive health service that should be provided for free, again, to prevent pregnancy, which itself is not a disease.”
WHO’s International Association for Research of Cancer on its website lists estrogen-progestogen oral contraceptives as among 122 carcinogenic agents. It also notes “convincing evidence” that the drug has a “a protective effect against cancer in the endometrium and ovary.”
“Natural methods of family planning or fertility awareness-based methods can be used and can be used very effectively with effectiveness rates comparable to hormonal birth control. I think that’s really important,” Duane said. “The World Health Organization recognizes fertility awareness-based methods as the only form of family planning with no medical side effects.”
Catholic ethics rejects the use of contraceptives.
John F. Brehany, executive vice president of the National Catholic Bioethics Council, warned that Catholics should not adopt a “contraceptive mentality.”
“We should understand and respect the fertility of our bodies through the lens of faith — knowing that we are part of a created order designed by the God of love and life,” Brehany told CNA. “Life and sex are best approached within God’s plan (and using medicine and technology consistent with that plan), not as a series of risk mitigation calculations.”