The use of oral contraceptives and hormone replacement therapy (HRT) may prevent brain aneurysms in post-menopausal women, according to findings presented at the Society of Neurointerventional Surgery annual meeting.

Previous trials have found that women who have already experienced menopause are among the most common high-risk populations. In order to better understand the connection between low hormone levels and this health problem, researchers enrolled 60 women aged 31 to 80 who had been diagnosed with aneurysms in a two-year study.

The team then surveyed the participants about their gynecologic history and hormone treatment use, and compared their responses to a control group of more than 4,600 women.

The researchers discovered that approximately 78 percent of the control group reported the use of oral contraceptives, while 60 percent of the aneurysm group had used these medications. Also, an estimated 45 percent of the aneurysm-free women used HRT, while only 24 percent of the study group had a history of HRT.

Michael Chen, co-author of the study, stated that these findings “support our hypothesis that drops in estrogen that occur in menstruation and particularly at menopause may explain why cerebral aneurysms are more frequently found in women.”

Patients who have been diagnosed with a brain aneurysm have a 15 to 20 percent chance of developing at least one more during their lifetime, The Aneurysm and AVM Foundation reports.