The use of oral contraceptives (birth control pills) for five years or more decreases the risk of ovarian cancer in later life by 50%.[81]
Combined oral contraceptive use reduces the risk of ovarian cancer by 40% and the risk of endometrial cancer by 50% compared to never users. The risk reduction increases with duration of use, with an 80% reduction in risk for both ovarian and endometrial cancer with use for more than 10 years. The risk reduction for both ovarian and endometrial cancer persists for at least 20 years.[19]
Taking oral contraceptives also reduces the risk of colorectal cancer, and improves conditions such as pelvic inflammatory disease, dysmenorrhea, premenstrual syndrome, and acne.[82]