A few months ago, I was driving to an engaged couples conference to speak on fertility awareness methods as an alternative to hormonal birth control. Less than five minutes from the site of the conference, I heard a commercial about birth control come on the radio. The ad implied that women\u2019s access to birth control was about to be drastically limited, with dire consequences. With new research out the University of Quebec suggesting that hormonal birth control (HBC) may interfere with women\u2019s ability to process fear in a healthy way, I have to wonder if fear-mongering ads about the loss of birth control access are a targeted marketing strategy.<\/p>\n\n\n\n
10 years ago, voices in the fertility awareness and natural family planning (NFP) space who dared discuss birth control\u2019s disastrous mental health effects\u2013from anxiety and depression to other emotional disturbances and suicidality\u2013were dismissed and outright ridiculed as paranoid zealots. Fast forward to 2024, and mainstream sources increasingly acknowledge<\/a> HBC\u2019s mental and emotional health impacts, albeit with caveats and insistence<\/a> that the benefits probably still outweigh the risks. But exactly how might HBC hurt mental health? <\/p>\n\n\n\n We know that fluctuating levels of estrogen<\/a> and progesterone in a natural menstrual cycle help women maintain healthy emotional regulation<\/a> [1]. Since HBC flatlines women\u2019s hormones, or, more accurately, stimulates tiny hormonal spikes<\/a> each day, it could be that the lack<\/em> of normal hormonal fluctuation explains the negative mental and emotional health effects many women experience on HBC. <\/p>\n\n\n\n A recent study done by researchers at the University of Quebec in Montreal and published in Frontiers in Endocrinology<\/em><\/a> provides further evidence of HBC\u2019s negative effects on users\u2019 emotional regulation. The Quebec researchers sought to understand whether and to what extent HBC plays a role in users\u2019 ability to healthily process fear, which is a key component of emotional regulation. Their findings suggest that hormonal birth control may actually alter the way users process fear [2]. <\/p>\n\n\n\n The study observed healthy Canadian adults between the ages of 24-35. 139 women were separated into three groups: 62 current oral contraceptive (OC) users, 37 past users, and 40 women who had never used OCs. The study also included a control group of 41 men. Since women have historically been left out of neurological research, it was important for the researchers to compare men\u2019s brains to women’s brains to recognize the base differences between the two sexes before making any conclusions.<\/p>\n\n\n\n Each participant provided a saliva sample for natural and synthetic hormone assessment and participated in an MRI scan that specifically focused on the fear-processing regions of the brain.<\/p>\n\n\n\n To understand how OCs affect the brain\u2019s ability to process fear, we need to first understand a little about the ventromedial prefrontal cortex (vmPFC). The vmPFC is key for decision making, memory, emotional regulation, and more. Together, the amygdala, hippocampus, hypothalamus, anterior insular cortex, dorsal anterior cingulate cortex, rostral anterior cingulate cortex, and<\/em> the vmPFC process fear. <\/p>\n\n\n\n The amygdala, hippocampus, and vmPFC specifically are chock full of sex hormone receptors, and the researchers zeroed in on the vmPFC to see if birth control impacts fear processing. <\/p>\n\n\n\n VmPFC tissue thickness<\/a> correlates with an ability to let go of fear and thus relax [3]. Thicker vmPFC translates to less generalized fear, greater mental and emotional resilience after trauma, and increased ability to let go of fear. Notably, feeling more or less fearful all the time, even about little things, is the predominant feature of generalized anxiety disorder. Thinner vmPFC generally translates to decreased tolerance of healthy kinds of fear, and greater fearfulness overall. <\/p>\n\n\n\n In the study, only the women who were currently using hormonal birth control had thinner vmPFCs than the men. Since the vmPFC helps to regulate and inhibit our response to emotions, a change in its thickness could play a role in how women who are taking hormonal birth control can regulate fear. Lead researcher Alexandra Brouillard commented<\/a>, \u201cThis part of the prefrontal cortex is thought to sustain emotion regulation, such as decreasing fear signals in the context of a safe situation. Our result may represent a mechanism by which [OCs] could impair emotion regulation in women.\u201d<\/p>\n\n\n\n The women on hormonal birth control, who had significantly thinner vmPFCs, would be expected to have a harder time calming down and \u201cextinguishing\u201d their fear. They would logically be more vulnerable to chronic anxiety than their non-user counterparts. This suggests not only that our hormones play a serious role in our brain structure, but also that altering those hormones may unnaturally affect brain tissue and functioning. <\/p>\n\n\n\n The researchers also looked at the dorsal anterior cingulate cortex (dACC) of the participants\u2019 brains, the part of the brain that promotes fear [2]. Like the vmPFC, the structure of the dACC was different between men and women. Compared to all three groups of women, the men\u2019s dACCs<\/a> were consistently smaller in volume than their female counterparts. Since larger dACCs correlate with higher levels of fear, this finding could explain why women, in general, tend to be more fearful than men. It also reinforced the understanding that our hormone fluctuations affect how the brain develops, as the process of hormonal fluctuation in men and women varies significantly. <\/p>\n\n\n\n Similar to non-users and the men, the women who had used OCs in the past did show thicker vmPFCs than the women still on it. This led the researchers to conclude that decreased fear tolerance due to OCs is likely a reversible problem. Since only the current OC users (but not past OC users) had a thinner vmPFC, the neurological effects of hormonal birth control may be reversible. <\/p>\n\n\n\n Future psychological and psychiatric research needs to study women, and lots of them. The Montreal researchers explained that even though women suffer anxiety far more than men, \u201cAs of 2012, less than 2% of fear-related [research studies] were conducted on female brains\u201d [2]. Concerningly, \u201cmale-only manuscripts are 9 times more common than female-only papers in neuroscience and psychiatry journals\u201d [2]. Most troublingly, \u201cFemale underrepresentation is mainly driven by the assumption that sex hormone fluctuations would lead to increased variability in results, albeit this argument has not been empirically supported\u201d [2]. Women who are naturally cycling should not be penalized for their biology<\/a>. And women who are on HBC deserve to know how it might affect their fear processing in addition to other aspects of mental and emotional health. <\/p>\n\n\n\n Future research also needs to take adolescent birth control use into account. We know adolescence<\/a> is a particularly delicate period for brain development, so women who started using hormonal contraceptives during that time could theoretically have more severe brain alterations than those who only used them in adulthood. <\/p>\n\n\n\n A Newsweek <\/em>analysis<\/a> of the Montreal study noted that birth control\u2019s impact on emotional regulation isn\u2019t exactly news, since \u201cA 2022 study published in Frontiers in Behavioural Neuroscience<\/em>, found that out of 72 people, those who used oral contraceptives felt more fear, anger<\/a> and disgust<\/a> than those who did not.\u201d<\/p>\n\n\n\n What does this mean for the 150 million<\/a> women who use HBC across the globe? Although the amount of research on its effects is increasing, there are still many unknowns regarding HBC\u2019s long-term or permanent impacts on women\u2019s health, especially in women who\u2019ve used it for decades, and those who started using it in adolescence. <\/p>\n\n\n\n Women are sometimes warned about some of the physical symptoms they may experience while on HBC, but there\u2019s often less education about the neurological and\/or emotional side effects, especially whether or not they may be reversible. This study\u2019s findings that HBC may decrease women\u2019s ability to healthily process fear represent the preliminary phase of extensive research that needs to be conducted to understand just how, how much, and how long HBC impacts brain health and emotional regulation. 70 years since the Pill\u2019s introduction, this research is long overdue. <\/p>\n\n\n\n Resources:<\/p>\n\n\n\n[1] Casto KV, Jordan T, Petersen N. Hormone-based models for comparing menstrual cycle and hormonal contraceptive effects on human resting-state functional connectivity. Front Neuroendocrinol. 2022 Oct;67:101036. doi: 10.1016\/j.yfrne.2022.101036. Epub 2022 Sep 17. PMID: 36126748; PMCID: PMC9649880.<\/p>\n\n\n\n[2] Brouillard A, Davignon LM, Turcotte AM, Marin MF. Morphologic alterations of the fear circuitry: the role of sex hormones and oral contraceptives. Front Endocrinol (Lausanne). 2023 Nov 7;14:1228504. doi: 10.3389\/fendo.2023.1228504. PMID: 38027091; PMCID: PMC10661904.<\/p>\n\n\n\n[3] Milad, Mohammed R et al. \u201cThickness of ventromedial prefrontal cortex in humans is correlated with extinction memory.\u201d Proceedings of the National Academy of Sciences of the United States of America<\/em> vol. 102,30 (2005): 10706-11. doi:10.1073\/pnas.0502441102<\/p>\n\n\n\n Additional Reading:<\/p>\n\n\n\n Estrogen is a key driver of the menstrual cycle. But it impacts your brain health, too<\/a><\/p>\n\n\n\n FAM Basics: Your hormones during a natural cycle vs. your hormones on the Pill<\/a><\/p>\n\n\n\nWho and what was researched?<\/span><\/h2>\n\n\n\n
Hormonal birth control alters the thickness of a part of the brain that processes fear <\/span><\/h2>\n\n\n\n
Thicker vmPFC tissue correlates with greater emotional resilience<\/span><\/h3>\n\n\n\n
Are women more predisposed to fear than men? <\/span><\/h2>\n\n\n\n
Are HBC\u2019s effects on fear processing reversible?<\/span><\/h2>\n\n\n\n
What else should future HBC research clarify? <\/span><\/h2>\n\n\n\n
How does this impact what we already know?<\/span><\/h2>\n\n\n\n