(Hailey Weiss/ TIME Magazine) — For people who want to prevent pregnancy, birth-control drugs come with an obvious reward. They also come with some small risks—including, for some forms, a slightly increased risk of breast cancer.
This has long been known about the most popular type: combined hormonal birth control, which is available in pill, patch, and ring form. These all contain both estrogen and progestin, a synthetic version of the naturally occurring reproductive hormone progesterone.
Less is known about the breast-cancer risks of progestin-only birth control, a type that’s growing in popularity because it only contains one hormone. By eliminating estrogen, these methods cut out some of the risks associated with the hormone, such as blood clotting.
But new data from the U.K. have allowed researchers for the first time to compare the breast-cancer risks of different popular types of hormonal birth control—and the study found no difference in risk between women using progestin-only birth control and those using methods that combine progestin and estrogen. (…)