Women with breast cancer might wonder if the birth control medications they took in the years before diagnosis could affect their chances of beating the disease — but City of Hope researchers and their colleagues recently showed that use of “The Pill” has no bearing on women’s mortality risk.

Oral contraceptive use has no effect on mortality in women later diagnosed with breast cancer, according to scientists.

Between 2006 and 2008, some 43.8 million women across the U.S. used oral contraceptives, which consist of variations of the hormones estrogen and progestin. Earlier research showed that use of modern, low-dose oral contraceptives does not increase the risk of developing breast cancer, or increases it only slightly for those currently taking it or who took it within a few years before diagnosis. But the few studies looking at relationships between oral contraceptive use and breast cancer deaths have been inconsistent.

Now an analysis of about 8,500 women shows that taking oral contraceptives regularly in the years before breast cancer diagnosis has no influence on a woman’s risk of dying from the disease. The research was published online in May in the journal Cancer Epidemiology, Biomarkers and Prevention.

Yani Lu, Ph.D., assistant research professor in the Division of Cancer Etiology, was lead author on the paper, while Leslie Bernstein, Ph.D., professor and director of the Division of Cancer Etiology, was senior author.

The scientists used data from the Women’s Contraceptive and Reproductive Experiences Study and the California Teachers Study for the project.

Collaborators included scientists from the University of Southern California, Fred Hutchinson Cancer Center in Seattle, University of Pennsylvania, Karmanos Cancer Institute in Detroit, and the Centers for Disease Control and Prevention. The California Breast Cancer Research Program funded the analysis.