Context

Oral contraceptives (OCs) were introduced in the early 1960s. Uptake was rapid in many Western countries and, by the mid-1970s, 20%–30% of women of reproductive age were current users. It is well established that women have a slightly increased risk of developing breast, cervical or liver cancer while taking OCs and for a few years after stopping. However, OCs also greatly reduce risk of ovarian and endometrial cancer and perhaps colorectal cancer.1 This risk reduction, at least for ovarian and endometrial cancer, persists for two to three decades after stopping OCs. This prospective study extends this body of evidence by examining the long-term balance of cancer risks and benefits associated with OC use.2