New research provides evidence that oral contraceptive use is related to changes in brain structure and function. The study, published in Hormones and Behavior, indicates that oral contraceptive use during puberty might impact stress reactivity and also increase brain activity when working memory is engaged.
“Oral contraceptives have been commercially available for over 60 years and are currently used by 150 million women worldwide. However, little is known about their behavioral and neurophysiological effects, especially during puberty/early adolescence, a critical period of development,” explained Nafissa Ismail, an associate professor at the University of Ottawa and the corresponding author of the study.
“We were particularly interested in investigating the effect of oral contraceptives on brain structure and function, especially in women who began taking oral contraceptives during puberty and adolescence.”
The researchers used functional magnetic resonance imaging or functional MRI (fMRI) to examine the brain activity and structure of 75 women as they completed a test of working memory. In addition, 140 women completed the Trier Social Stress Test, an experimentally verified stress-inducing scenario in which the participants are asked to give a speech and do mental arithmetic.
“This study is the first to examine the age-dependent effect of OC use on brain structure and function during working memory tasks,” the researchers said.
Ismail and her colleagues found that oral contraceptive use was linked to increased activation in the prefrontal cortex during working memory processing for negatively arousing stimuli, such as images of a gun. Women who started using oral contraceptives during puberty or adolescence displayed a blunted cortisol response following the stress test.
“We found that there are differences in brain structure and function between oral contraceptive users and non-OC users. Oral contraceptive users display different brain activity during working memory processing of negative images compared to non-OC users,” Ismail told PsyPost.
“Women who started using oral contraceptives during puberty/adolescence display a blunted stress response and experience different brain activity during working memory processing of neutral images compared to women who started using oral contraceptives during adulthood.”
In particular, women who started using oral contraceptives during puberty or adolescence displayed more brain activity in the bilateral lingual gyrus, midtemporal gyrus, pre-central gyrus, and insula during working memory processing of neutral images.
Oral contraceptive use during puberty was also associated with structural changes in brain regions implicated in emotion regulation and memory, such as the fusiform gyrus and precuneus.
“Given that this was not a longitudinal study, we unfortunately don’t know whether the difference in stress reactivity and brain activity between women who started using oral contraceptives during puberty/adolescence and those who began using oral contraceptives in adulthood is due to the age of onset of oral contraceptive use or due to longer duration of usage,” Ismail said.
The findings could shed light on how oral contraceptive use is related to women’s mental health.
“It could provide a neural mechanism for why some women develop mood-related disorders following oral contraceptive use. One possibility is depression. Some women have complained of depression symptoms during oral contraceptive use. We need to be aware of it and talk to our physician if we are experiencing these symptoms,” Ismail explained.
“The goal of our research is not to worry women or to discourage them from taking oral contraceptives. We just want to advise them so that they can make an informed decision about what is best for them. There is still a lot of work to be done to fully understand the impact of oral contraceptives on women’s health.”
The study, “Use of the birth control pill affects stress reactivity and brain structure and function“, was authored by Rupali Sharma, Samantha A. Smith, Nadia Boukina, Aisa Dordari, Alana Mistry, Briallen C. Taylor, Nereah Felix, Andrew Cameron, Zhuo Fang, Andra Smith, Nafissa Ismail.