STUDY: Birth control pill may help prevent uterine cancer

SAN FRANCISCO -- There is encouraging health news for women taking contraceptive pills.

A new study shows the pill has prevented 200,000 cases of uterine cancer in the last decade.

Researchers say for every five years of taking the pill, a woman lowers her risk by 25 percent.

Scientists believe the pill tricks the body into thinking it's pregnant, and lowers the body's natural estrogen level.

That effect continues even after a woman stops taking the pill.

The study is in the journal Lancet Oncology.