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.
STUDY: Birth control pill may help prevent uterine cancer