Oral contraceptives have been commercially available for about 60 years and are widely used today. It’s estimated that over 150 million women around the world use birth control pills. Although many people are already aware of the physiological side effects of oral contraceptives, relatively little is known about their impact on the brain and on women’s mental health.
New research headed up by graduate student Rupali Sharma and lead by Nafissa Ismail, associate psychology professor and uOttawa research chair in stress and mental health, and uOttawa psychology professor Dr. Andra Smith, reveals differences in stress reactivity, brain structure, and function in women who started taking oral contraceptives during early adolescence.
Over 80 hours of imaging data collected at The Royal’s Brain Imaging Centre illustrates the brain activity of female volunteers while they took “emotional memory tests,” which involved recalling images that were either negative, positive, or neutral.
The women who’d been taking oral contraceptives showed more activity in the prefrontal cortex when looking at the negatively-charged pictures. In other words, their brains worked harder compared to women who’d never taken oral contraceptives.
Sharma speculates that women’s brains on the birth control pill could be more sensitive to negatively-charged subject matter. “It could also represent a higher vigilance for negative emotions, but somewhere in their brains, they are more sensitive to this negatively-charged information,” says Sharma.
“Whether that could translate to everyday social interactions, like minor stressors in daily life, obviously still needs to be investigated, but at a neurophysiological level, their brains are exerting more energy in order to remember these pictures.”
Another part of the study, which took place at the Integrated Neurocognitive & Social Psychophysiology Interdisciplinary Research Environment (INSPIRE) Laboratory at uOttawa, found that women who started taking oral contraceptives during early adolescence have a dulled response to stress compared to women who started taking birth control later.
“The message is not to deter women from using the birth control pill, it’s more about educating women about their brain and how oral contraceptives can have an impact.”
Sharma, who recently completed her PhD at the University of Ottawa, hopes that these initial findings will help women make informed decisions when choosing what method of contraception to use.
Sharma says women’s mental health was her main reason for undertaking this research.
“We know that during adolescence, when women experience their very first menstrual cycle, they’re already one-and-a-half to three times more likely to experience depression or anxiety compared to men. We already see anecdotally, and with some research, that women who are on the pill are even at a greater risk of developing depression and anxiety.”
Although Sharma and her colleagues didn’t see any differences in depression scores between the users of oral contraceptives and non-users, the findings might shed some light on other behaviours commonly linked to birth control pills.
“For women who experience more subtle mood changes like crying spells, or just being irritable, or maybe have more of a pessimistic outlook or self-deprecating thoughts, I think these differences that were found in brain structure and brain function could maybe give light to some of those mood differences that women experience when they go on birth control,” says Sharma. “This could be a very early mechanism for why some women go on to develop depression or mood swings or changes in more negative mood, but we can’t conclusively say that these differences are specifically related to depression.”
Sharma hopes these findings will encourage women to include mental health in the conversation when they talk to their family doctor or gynecologist about contraception.
“The message is not to deter women from using the birth control pill, it’s more about educating women about their brain and how oral contraceptives can have an impact.”