New research has revealed a possible link between taking the oral contraceptive pill and changes in how the brain responds to fear.
Researchers in Canada investigated the current and lasting effects of oral contraceptive use.
They found that women currently using oral contraceptives had a thinner ventromedial prefrontal cortex, compared to men and other groups of women.
The ventromedial prefrontal cortex has a variety of functions, but it is referred to as the “fear-inhibiting region”.
“This part of the prefrontal cortex is thought to sustain emotion regulation, such as decreasing fear signals in the context of a safe situation,” said researcher and first author of the study, Alexandra Brouillard.
“Our result may represent a mechanism by which oral contraceptives could impair emotion regulation in women.”
Brouillard and colleagues studied 180 healthy men and women aged between 25 and 35.
The sample included 139 women who were currently using the pill, had previously used it, or who had never used any hormonal contraceptives.
The scientists used the participants’ saliva to measure their natural and synthetic sex hormone levels and used magnetic resonance imagining (MRI) to scan their brains.
The study found that men showed a smaller volume of a fear-promoting region of the brain than women, regardless of their contraceptive use.
This means that it “could represent a female predisposition to fear promotion” with oral contraceptives exacerbating this vulnerability.
The study concluded that taking combined oral contraceptives can affect fear-related brain morphology.
Researchers highlighted that they could not settle this conclusion because changes in brain region size do not necessarily correlate to changes in behaviour.
These findings could help deepen an understanding of fear-related conditions predominantly affecting women, such as anxiety disorders and post-traumatic stress disorder.
The team of researchers will continue to investigate this area.