As misinformation about women's health spreads faster than ever, doctors say new research into the risks of hormonal birth control highlights the challenge of communicating nuance in the age of social media.
The large study, which was conducted in Sweden and tracked more than 2 million teenage girls and women under age 50 for more than a decade, found that hormonal contraception remained generally safe, but also found small differences in breast cancer risk depending on the hormones used in the formulation. Additionally, the researchers observed a small short-term increase in breast cancer diagnoses among current or recent users. These results are consistent with previous large studies, including Analysis of the Danish register for 2017 And Meta-analysis 2023.
It was published online on October 30 at JAMA Oncology.
Doctors say these study findings will not change how they counsel patients and that women should not stop using birth control.
However, TikTok is filled with factually incomplete warnings that birth control causes cancer and is as dangerous as smoking. Reproductive health advocates warn that such research can easily to be taken out of context online and boil them down to one alarming number.
Case in point: Studying reported that women who used hormonal contraceptives had approximately 24% higher rates of breast cancer than women who did not. But because breast cancer is still rare in young women, this translates to an increase from about 54 to 67 cases of breast cancer per 100,000 women per year—about 13 additional cases per 100,000 women, or about one additional case per 7,800 hormonal contraceptive users per year.
Co-authors Åsa Johansson and Fatemeh Hadizadeh, epidemiologists Uppsala Universitysaid the increase is modest and short-term, with the risk highest during ongoing use and dissipating within five to 10 years of cessation.
Rachel Fey, interim co-CEO of Power to Decide, a group whose mission is to provide accurate information about sexual health and contraceptive methods, said it's the kind of nuance that tends to disappear on social media. “I'm really angry about it because it's designed to scare people like me away from birth control, which has made my life so much better in so many ways,” she said. “It's really frustrating… especially when it's given without context. And then, in the age of social media, it can just take off without anyone who knows what they're talking about providing that context.”
The researchers also found that the risk was slightly higher with some progestins, such as desogestrel, which is found in combined oral contraceptives such as Cyred EQ, Reclipsen, Azurette and Pimtrea, but was not increased with others, such as medroxyprogesterone acetate injections sold under the brand name Depo-Provera.
How to interpret the results
Some experts say the results should be viewed with caution because the study looked at both invasive breast cancer and early, noninvasive lesions known as tumors in situ, growths that may never become life-threatening. Including these precancerous cases may make the overall risk of clinically significant disease higher than it actually is.
“A significant proportion of the ‘cases’ would never develop into invasive breast cancer,” said Lina S. Mørch, senior researcher and team leader at the Danish Cancer Institute. Mörch was not involved in the Swedish study. She added that experts should wait for more data separating early and late stages of cancer before setting new rules or warnings about specific hormones.
Conversation between doctor and patient
While scientists debate how to interpret the finer points of the data, doctors stress that for most patients, the study confirms what they've already discussed in the exam room: Hormonal contraceptives are generally safe, and solutions should be tailored to each woman's needs and values.
Katherine White, chief of obstetrics and gynecology at Boston Medical Center, said the study won't change the way she talks to her patients.
“When counseling patients about contraceptive options, I focus on their past experiences with contraception, their medical history, and what is important to them regarding their birth control method and pregnancy planning (if applicable),” White wrote in an email. “Side effects and risks of methods are already a key part of my counseling for both hormonal and non-hormonal methods.”
Other doctors noted that there are other contraceptive options.
Eleanor Bimla Schwartz, chief of internal medicine at Zuckerberg San Francisco General Hospital, said, “For those who prefer hormone-free contraception, the copper IUD provides safe, comfortable, and highly effective contraception for more than a decade after insertion and is quickly reversible when pregnancy is desired,” referring to a type of long-acting intrauterine device.
Mary Rosser, director of comprehensive women's health at Columbia University Irving Medical Center, said this was a large, high-quality study that looked at many types of hormones over many years. But she added that doctors should not change their recommendations just yet.
Johansson and Hadizadeh stressed that the results should serve as a basis for shared decision-making rather than cause alarm. “It may be reasonable to consider formulations associated with lower observed risk in our data,” they said. They noted that products containing medroxyprogesterone acetate, drospirenone, or levonorgestrel are associated with a lower risk, while long-term use of contraceptives containing only desogestrel is best avoided when other options are appropriate.
Putting risk into perspective
Hormonal birth control provides many health benefits beyond preventing pregnancy. It can relieve heavy periods, relieve pain from endometriosis, and reduce the risk of ovarian and uterine cancer for years after you stop. Mörch noted that even small risks are worth discussing, but said decisions should be based on women's “values and preferences.”
White said it's important to see the big picture. “The risk of unintended pregnancy is 85% for people who do not use birth control, so any risks of birth control must be weighed against the risk of unexpected pregnancy,” she wrote.
