Bronnick, M. K., Okland, I., Graugaard, C., & Bronnick, K. K. (2020). The Effects of Hormonal Contraceptives on the Brain: A Systematic Review of Neuroimaging Studies. Frontiers in Psychology. https://doi.org/10.3389/fpsyg.2020.556577
Bronnick MK, Okland I, Graugaard C, Bronnick KK. The Effects of Hormonal Contraceptives on the Brain: A Systematic Review of Neuroimaging Studies. Frontiers in Psychology. 2020. doi:10.3389/fpsyg.2020.556577
Bronnick, Marita Kallesten, et al. "The Effects of Hormonal Contraceptives on the Brain: A Systematic Review of Neuroimaging Studies." Frontiers in Psychology, 2020.
Most imaging studies link hormonal contraceptives to brain changes
Most of 33 brain imaging studies found brain changes linked to hormonal contraceptive use. This 2020 review compared women on hormonal contraceptives with women who were not. Two trials used one sample of 30 women. One study enrolled only teenagers.
Key Findings
The review included 33 articles: 10 studies of brain structure and 23 studies of brain function.
Most studies reported changes in brain structure or function tied to hormonal contraceptive use. Regions with reported changes included the amygdala, hippocampus, cingulate gyrus and prefrontal cortex.
The only two randomized trials used one sample of 30 women with earlier negative mood on hormonal contraceptives. Women randomized to the drug showed depressed mood after 1 month of use.
One study investigated a purely adolescent sample. No study examined structural changes in drug-naïve teenagers.
Interpretation
The review pools studies of uneven quality. Most other studies compared women who chose a contraceptive with women who did not. The authors say this makes cause impossible to establish. Most studies had small samples, and several used whole-brain image analyses without correction for multiple testing, which may have produced false positives. Findings conflicted: one study found a larger parahippocampal gyrus in users and another a smaller one. The trial women all had earlier negative mood effects, so their results cover only that group. The authors call effects on teenagers unresolved.
RRM Context
Restorative reproductive medicine works with the ovulatory cycle. Hormonal contraceptives are suppressive medications that act on that cycle. A Danish national cohort study cited in the review found a correlation between use and a later first diagnosis of depression. The correlation was strongest in adolescent women.
Our editorial summary of this paper, not the article's abstract.
Abstract
Background
Hormonal contraceptive drugs are being used by adult and adolescent women all over the world. Convergent evidence from animal research indicates that contraceptive substances can alter both structure and function of the brain, yet such effects are not part of the public discourse or clinical decision-making concerning these drugs. We thus conducted a systematic review of the neuroimaging literature to assess the current evidence of hormonal contraceptive influence on the human brain.
Methods
The review was registered in PROSPERO and conducted in accordance with the PRISMA criteria for systematic reviews. Structural and functional neuroimaging studies concerning the use of hormonal contraceptives, indexed in Embase, PubMed and/or PsycINFO until February 2020 were included, following a comprehensive and systematic search based on predetermined selection criteria.
Results
A total of 33 articles met the inclusion criteria. Ten of these were structural studies, while 23 were functional investigations. Only one study investigated effects on an adolescent sample. The quality of the articles varied as many had methodological challenges as well as partially unfounded theoretical claims. However, most of the included neuroimaging studies found functional and/or structural brain changes associated with the use of hormonal contraceptives.
Conclusion
The included studies identified structural and functional changes in areas involved in affective and cognitive processing, such as the amygdala, hippocampus, prefrontal cortex and cingulate gyrus. However, only one study reported primary research on a purely adolescent sample. Thus, there is a need for further investigation of the implications of these findings, especially with regard to adolescent girls.
