Oral contraception can change the part of the brain responsible for emotions, fear and anxiety, which may make women on the pill more likely to engage in unsafe behavior.
Researchers from Canada studied 139 women aged 23 to 35 and found that those who used oral contraceptives had thinner areas in their frontal lobe than those who had never used OCs or had stopped taking them.
This thinning is thought to impact social behavior and impulsivity, potentially causing women on OCs to have lower inhibitions, more risk-taking, and less anxiety.
The team said more research needs to be done, but their results suggest that exposure to sex hormones plays a role in the structure of the nervous system.
Alexandra Brouillard, a researcher at the Université du Québec à Montréal and first author of the study, told DailyMail.com that her team found that the effect of current OC use on this brain region was related to exposure to synthetic estrogen that is present in the pills.
More than 150 million women around the world use oral contraceptives, and birth control pills are between 93 and 99 percent effective at preventing pregnancy
said Brouillard: ‘In our research we show that healthy women who currently use (oral contraceptives) have a thinner ventromedial prefrontal cortex than men.
‘It is thought that this part of the prefrontal cortex supports emotion regulation, such as reducing fear signals in the context of a safe situation.
‘Our result may represent a mechanism by which COCs may impair emotion regulation in women.’
More than 150 million women around the world use OCs, and birth control pills are between 93 and 99 percent effective at preventing pregnancy.
OC is generally considered safe, but there are some risks associated with it, including breast pain, mood swings, weight gain, and stroke.
Of the female subjects, 62 were currently using oral contraception, 37 had previously used OCs, and 40 women had never taken the pills. Researchers also included 41 men for comparison.
The team performed MRIs to study the gray matter volume and cortical thickness of brain areas involved in processing information, regulating emotions, retaining memories and controlling muscles, as well as in sensory perception and decision-making .
Gray matter – also called gray matter – is known as the cortex of the brain and forms the outermost layer of the brain.
Greater cortical thickness is thought to be associated with intelligence, while thinning is associated with cognitive impairment.
Compared to men, all three groups of women had greater gray matter volume in a part of the brain related to learning, self-control and executive control.
This could be a reason why men are generally more impulsive than women.
The study also found that only women who were currently using birth control experienced thinning in a part of the brain responsible for processing risk and fear and managing emotions.
The thinning of this area is thought to cause inhibitory deficits, or the loss of social behavior and impulsivity, especially as it is related to the function of the amygdala, the gray matter involved in experiencing emotions.
A reduced amygdala reduces fear conditioning – when a person comes to associate something with a negative outcome and has a fearful response.
This can lead to women on OCs having lower inhibitions, more risk-taking, and less fear in unsafe situations.
However, Brouillard told DailyMail.com that researchers still need to investigate whether their anatomical findings are associated with significant changes in behavior or mental status.
She said it would be “too presumptuous” to conclude that these brain changes are directly linked to riskier and unsafe behavior.
However, scientists do know that these brain regions are involved in such behavior.
Brouillard said women prescribed contraception are made aware of the physical effects of the medication, such as lack of menstruation and ovulation.
However, the impact of OCs on brain development is rarely addressed.
Given how widespread birth control use is, it is important to better understand the pills’ current and long-term effects on brain anatomy and emotional regulation, the researchers said.
Brouillard continues: ‘The aim of our work is not to prevent the use of COCs, but it is important to realize that the pill can have an effect on the brain.
‘Our goal is to increase scientific interest in women’s health and raise awareness about early COC prescribing and brain development, a very unknown topic.’
The study was published Tuesday in the journal Frontiers in Endocrinology.