Beyond preventing pregnancy, birth control pills have shown to help regulate periods, clear up acne, and even reduce your risk of ovarian cancer. Seems pretty sweet, right? Well, it turns out the pill may have a dark side: It could increase your risk of breast cancer, according to a study in the journal Cancer Research.

In the study of more than 23,000 women ages 20 to 49, researchers found that women who'd used the pill within the last year had a 50 percent increased risk of breast cancer compared to those who previously or never used the pill. What's more, women's risk of the disease varied depending on what type of oral contraceptive they took. Birth control pills containing high-dose estrogen increased breast cancer risk 2.7-fold and those containing moderate-dose estrogen (the most commonly prescribed pill in the study) increased the risk 1.6-fold. Birth control pills containing low-dose estrogen didn't increase women's breast cancer risk.

Breast cancer is a hormone-driven disease and hormones in birth control pills, especially estrogen, may be responsible for the increased risk, says study author Elizabeth Beaber, Ph.D., M.P.H., of the Fred Hutchinson Cancer Research Center in Seattle. Oral contraceptives may increase breast cell proliferation, which causes tumors to grow. Future studies are needed to confirm these findings.

So should you ditch your pack? Not so fast. "It's important to remember that breast cancer is rare among young women and there are other health benefits associated with oral contraceptive use," Beaber says. Plus, previous studies show that your breast cancer risk declines after stopping oral contraceptives. For now, keep popping your pill. If you're concerned about your risk or have a family history of breast cancer, talk to your health care provider and discuss any other steps you could be taking to reduce your risk. Research shows losing weight if you're overweight, quitting smoking, minimizing your alcohol intake, and getting plenty of exercise are among the most effective ways to ward of the big C.