In this week's PLoS Medicine, a case-control study conducted by Margaret Urban and colleagues at the National Health Laboratory Services in Johannesburg, South Africa, provides new estimates of the risk of specific cancers of the female reproductive system associated with use of injectable and oral contraceptives.

The researchers report that use of these contraceptives is associated with a transiently increased risk of breast and cervical cancer, and that extended use is linked to a reduced risk of ovarian and endometrial cancer.