Suppressing ovulation may be beneficial.

A biological link between half of all ovarian cancers and the number of times a woman ovulates over her lifetime has been identified by researchers at Duke University Medical Center, Durham, N.C., suggesting that ovulation suppression has a protective effect. The scientists believe that constant ovulation, which causes cells in the ovary to divide, is likely to damage spontaneously DNA in those cells over time. That can result in mutations to a critical regulatory gene, known as p53, that normally stops cells from proliferating into cancer.

"When a woman ovulates, the egg that is extruded from the ovary blows a hole in the surface of the ovary," notes Andrew Berchuck, professor of gynecologic oncology. "The epithelial cells, where the cancer starts, line the surface of the ovary and they have to proliferate to fill in the hole." The findings indicate...