PHILADELPHIA (CBS) – A new study shows birth control could be linked with the development of a rare type of brain tumor.

According to CBS News, the Danish study found women under 50 who had glioma were 90% more likely to have used contraceptives for at least five years. That’s compared with women from the general population, who had no history of the brain tumor.

“A nearly two-fold increased risk of glioma was observed among long-term users of hormonal contraceptives,” researchers write.

The findings are published in the British Journal of Clinical Pharmacology. In the study, scientists looked at government data on women between 15 and 49 who had developed a glioma between 2000 and 2009. There were 317 glioma cases, and nearly 60 percent of those women had used contraceptives at some point. That’s compared to the more than 2,100 women not afflicted with glioma — about half of those women had used contraceptives.

Researchers say use of birth control pills or other hormonal contraceptives did seem to up the risk for glioma, and that risk appeared to rise with duration of use; however, the findings should be taken with a grain of salt.

According to the study’s leader Dr. David Gaist, just five out of 1,000 Danish women develop glioma per year, and that figure includes those who take the Pill.
In his words, “an overall risk-benefit evaluation favors continued use of hormonal contraceptives.”

To read more on the study, click here.