A new study looks at how oral contraceptives affect cancer risk. ALICE PARK January 19, 2018 In the U.S., nearly all sexually active women have used a form of birth control at some point in their lives, and 11 million women rely on the pill. In a new study published in JAMA Oncology, researchers explore how oral contraceptives, which affect women’s hormone levels to prevent pregnancy, affect cancer risk. They found that women taking the pill lowered their risks of ovarian and endometrial cancer—a known benefit of the pill. The researchers also analyzed other factors that might affect the risk, including obesity, smoking status and physical activity levels. In addition to finding that the risk of endometrial and ovarian cancers were lower among women who used the pill, the study found that the longer women were on oral contraceptives, the lower their risk was. For those taking the pill for 10 years or more, the risk of ovarian cancer was 40% lower compared to women who had neve...