“As the findings stack up, many women are unaware of the risks posed by oral contraceptive use prior to pregnancy,” says lead study author Chris Kahlenborn, M.D., of Altoona Hospital in Altoona. He says the discrepancy between risk and patient awareness prompted the meta-analysis, which involved extracting data from 34 studies on whether oral contraceptive (OC) use is associated with pre-menopausal breast cancer. Included in the studies were women who were pre-menopausal or younger than 50 and who had been, in most cases, diagnosed with breast cancer during or after 1980.

"As I studied the medical literature, I noticed that a trend appeared," says Kahlenborn. "Namely, OC use prior to first-term pregnancy seemed to consistently increase the risk of pre-menopausal breast cancer. Although the trend was apparent, pre-menopausal women have continued to hear that OCs are basically safe." Rather, patients should know that sustained oral contraceptive use prior to pregnancy increases a pre-menopausal woman's risk of developing breast cancer, says Kahlenborn. He says physicians should better inform their patients of the risks associated with oral contraceptives and calls it a "clear-cut informed consent issue."

The study noted that 21 out of 23 retrospective studies have shown an increased risk of breast cancer in women who took oral contraceptives prior to pregnancy. It also showed that those women experienced an increased risk of 44 percent. What's more, in 2005, the World Health Organization officially classified oral contraceptives as a class one carcinogen, the study's authors say. These are staggering results given that more than 45,000 women each year develop breast cancer prior to menopause, Kahlenborn says.

MEDICA.de; Source: Mayo Clinic