Certain Forms of Birth Control May Promote Brain-tumor Growth

In a recent study published in the British Journal of Clinical Pharmacology, researchers from Odense University Hospital and the University of Denmark found that women taking hormonal contraceptives — those containing estrogen, progestin or combination of both — showed higher rates of glioma development. The study raises questions about the connection between oral contraceptives and brain cancer, but should not yet be interpreted as a reason for women to stop taking birth control. Using data from Denmark’s national registries of health records, cancer cases and prescriptions, researchers focused on women from age 15 to 49 diagnosed with glioma, and then analyzed whether they were prescribed contraceptives, and for how long. Results of the study showed that overall, women who had used hormonal contraceptives at any point in their lives had a 50-percent higher risk of developing the brain tumors, compared to those who had not used them. Women who used the birth control for more than five years nearly doubled their risk of cancer. Additionally, women using progestin-only birth control had a slightly higher risk of developing gliomas; while it’s not clear why, researchers suspect that obesity may be playing a role. However, because gliomas are rare, the doubling of an already rare event is still a small risk. Glioma rates have not spiked since the introduction of hormonal contraceptives, and researchers agree that the correlation deserves discussion and more study. To read more about this study, click here.