The Link Between Birth-Control Pills And Breast Cancer

A new study finds that pills with a high level of estrogen increase breast-cancer risk significantly. But that still might not mean you should change your prescription.  The birth-control pill is regularly hailed as one of the greatest medical advancements for women. Breast cancer, meanwhile, is considered one of the biggest health threats.

The only problem? There’s some evidence that the first increases your risk of the second. A new study out today suggests that having recently taken birth-control pills increases breast cancer risk by about 50 percent. Women who were on a formulation of the pill with an especially elevated level of estrogen nearly tripled their risk of getting breast cancer, and a pill with even a moderate amount of the hormone increased the risk by about 60 percent.

For the study, published in the journal Cancer Research, scientists at the Fred Hutchinson Cancer Research Center and the University of Washington in Seattle followed 1,102 women diagnosed with breast cancer, most of whom were in their 40s. Rather than rely on self-report data, the researchers dug into the women’s pharmaceutical records to determine the exact oral contraceptives they were taking.  They divided the types of pills into three categories: Those formulated with a low level of synthetic estrogen, or about 20 micrograms of ethinyl estradiol; those with a moderate dose, or 30 to 35 micrograms of ethinyl estradiol or 50 micrograms of mestranol; and those with a high dose, or 50 micrograms of ethinyl estradiol or 80 micrograms of mestranol...