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Peeling the layers off hormonal contraception: the effect on emotion regulation and memory

Over 151 million females worldwide use hormonal contraceptives (HCs), from oral pills, vaginal rings, implants, IUDs, to patches, with combined oral contraceptives being the most common. HCs are also prescribed as treatment for irregular cycles, PMS symptoms, endometriosis, acne, heavy bleeding, or menstrual pain, and may lower the risk for ovarian and uterine cancers. 


Mechanisms & neural effects


So, how do they work? Hormonal contraceptives contain synthetic forms of hormones, differing in formulation and pharmacokinetics from their endogenous analogues. One of the mechanisms by which HCs work is by inhibiting follicular development, and thus ovulation. As these contraceptives increase progesterone in the body, the hypothalamus in the brain decreases the production of follicle stimulating hormone and luteinising hormone. This, in turn, leads to follicular development inhibition, which leads to no estradiol being produced by the follicle - thus preventing ovulation. 


 "Women using hormonal contraceptives rated their emotional reactions as stronger compared to the naturally cycling participants"

With the brain being a neuroendocrine organ, this mechanism of hormonal contraception impacts the brain and, relatedly, behaviour. Sex hormones, such as oestrogen and progesterone, have been found to affect both the structure and function of the brain, as well as neurotransmission. Moreover, brain regions such as the amygdala, hypothalamus, and hippocampus have oestrogen and progesterone receptors, thus having the potential to affect emotions, regulation, and memory respectively. Nonetheless, despite hormonal contraceptives' widespread use, their cognitive and emotional effects remain underresearched.


New research efforts


A recent study by Brandao et al. investigated hormonal contraceptives’ effects on emotion and cognitive processes, researching whether emotional reactivity, emotional regulation, and memory were different between individuals using hormonal contraception vs. those who are naturally cycling. 


 The researchers were interested in 3 key things: whether women using HCs are more or less reactive to positive/negative stimuli compared to naturally cycling women, whether they were able to apply emotion regulation strategies when viewing these emotional stimuli, and which strategy would be the most successful, especially when viewing negative stimuli. The emotional regulation strategies used were: 

  • Distancing (interpreting a negative stimulus objectively, as if viewing from a third-person perspective), 

  • Reinterpretation (reframing or changing your thoughts about the image), and 

  • Immersion (primarily used for positive images; involves imagining positive events from the image as close to the observer). 


Lastly, they wanted to test the participants' memory of the stimuli. 


The study had 179 women, of which 87 were using hormonal contraception, and 92 were naturally cycling. These women were randomly assigned to one of 3 groups: 

  1. Control (no emotion regulation strategies, just viewing the images) 

  2. Distancing and immersion (distancing for negative images, immersion for positive ones)

  3. Reinterpretation and immersion (reinterpretation for negative images, immersion for positive ones)


Shortly after viewing the images and applying the regulation strategies, participants underwent a surprise memory test, during which they were asked about the details of the images they just viewed. The scientists measured emotional reactivity by asking the participants to rate their emotional response to the images, emotional regulation success by asking if their emotions changed after they applied the strategy, and memory by testing how well they were able to remember the images. 


What did they find?


From this experiment, they found that women using HCs rated their emotional reactions as stronger compared to the naturally cycling participants. All women were able to successfully apply the emotion regulation strategies, but the distancing strategy worked better than reinterpretation for negative stimuli for HC users. Meanwhile, for positive images, the immersion strategy worked best for both HC and NC groups. In terms of memory performance, regardless of strategies used (distancing vs. reinterpretation), it was found that HC users remembered fewer details of the negative stimuli. 


These findings suggest that HC usage could lead to larger emotional reactions, feeling emotions at a higher intensity, or increased sensitivity to emotional stimuli. On the other hand, learning emotion regulation strategies regardless of HC usage could be increasingly helpful, given that it seemed effective for both groups. From the memory tests, they found that HC users were least likely to remember general information or details of the negative stimuli viewed. The scientists think this could be protective in the context of depressive symptoms; remembering less details could lead to less rumination, which may maintain or exacerbate negative mood. The findings of this study certainly repeat those of previous studies finding that HCs influence aspects of emotional processing and memory, but the field still requires nuanced research to find the specific aspects and pathways it affects. 


"Hormonal contraceptive users were least likely to remember general information or details of the negative stimuli viewed"

Importantly, the scientists acknowledge some limitations in their study. The study is cross-sectional, meaning that it compares HC users and non-users at one time, rather than tracking changes within an individual over time with HC start/stop. Participants were mostly using combined oral contraceptives (with only a small percentage using other kinds of contraceptives), so the results may not apply to different types of HCs. They also acknowledge that their measures were lab tasks (viewing images, surprise memory tests), which, while informative, are much less complex than real-world emotional experiences. Lastly, the pattern of reduced memory for details of negative events in HC users may be protective, but more research is required to understand when this pattern is helpful versus potentially limiting.


What next?


Dr Brandao and her collaborators call for more research that includes different types of contraceptives (pills vs. IUDs vs. implants; progestin-only vs. combination), is longitudinal, explores neurobiological mechanisms such as neuroimaging and hormonal assays, and determines which individual factors particularly would play a role (e.g. mood history, cognitive style, or hormone sensitivity). 


This new research answers some questions and builds a path forward to better understanding of brain and reproductive health. Since emotion regulation and memory are factors that play a role in mental health it is beneficial to understand how HCs can influence these processes so that women can make more informed choices about their reproductive and mental health. 



References 


This article was written by Peehu Jain and edited by Julia Dabrowska, with graphics produced by Lilly Green. If you enjoyed this article, be the first to be notified about new posts by signing up to become a WiNUK member (top right of this page)! Interested in writing for WiNUK yourself? Contact us through the blog page and the editors will be in touch.

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