More than 16 million American women who use hormonal contraceptives like birth control pills have a new reason to weigh their options.
For decades, doctors have warned that older formulations of birth control pills increase the risk of developing breast cancer. Over the years, new formulas for the medications which combine lower doses of estrogen with progestin have been introduced.
The widely-held belief was that these new varieties of birth control pills were safer, and using them didn't increase your cancer risk as much as older versions of the medicine. But a new study proves that just isn't true.
The study, published in the New England Journal of Medicine, analyzed records from the Danish health system, tracking 1.8 million women, their birth control prescriptions, and their cancer diagnoses.
The study's head, epidemiologist Lina Morch, said that she hoped the results would prove one type of medication was "a better alternative" for women, but instead they revealed that "none of these products are risk-free."
In fact, women who use modern birth control pills or recently used them have a 20 percent higher breast cancer risk than women who never used them. That rate is equal to about one extra case of breast cancer for every 7,500 women, which is very similar to the rate for older birth control pills.
Researchers shared other warnings about birth control pills, but also a silver lining to the new study.