Hormonal contraceptive use tied to changes in brain morphology in a densely-sampled female
Poster No:
1714
Submission Type:
Abstract Submission
Authors:
Elle Murata1, Caitlin Taylor1, Laura Pritschet2, Emily Jacobs1
Institutions:
1University of California, Santa Barbara, Santa Barbara, CA, 2University of Pennsylvania, Philadelphia, PA
First Author:
Co-Author(s):
Introduction:
Though millions of people worldwide use hormonal contraceptives, their impact on brain morphology is remarkably unclear. Existing studies show both decreases and increases in brain volume in response to hormonal contraceptive use (Lacasse, 2024). These conflicting findings are likely methodological by nature, limited by small cohort sizes and inconsistencies in formulation, initiation and duration of administration, and schedule of use in the hormonal contraceptive study groups (Taylor, 2021). Additionally, most studies investigating the effects of hormonal birth control on the brain utilize cross-sectional approaches, which cannot capture day-to-day changes in the brain occurring in tandem with the fluctuating hormone levels (Pritschet, 2021). To address these limitations, we applied a precision imaging approach in one individual to map the global and regional impact of hormonal contraceptive use on brain morphology.
Methods:
The present investigation employed a dense-sampling design to obtain MRI, endocrine, and mood assessments from a healthy adult female every 24 hours for 30 days across a complete menstrual cycle ("28&Me") and again one year later following 10 months on a combined oral contraceptive pill ("28&OC") for n=60 time-locked assessments (cf. Pritschet, 2020; Taylor, 2020). In the present analyses, we characterized the impact of combined oral contraceptive use on global and regional brain morphology relative to the cycling state. Measures of cerebrospinal fluid, ventricle size, cortical and subcortical volumes were calculated by running T1w images through the longitudinal recon-all pipeline from FreeSurfer (Dale, 1999; Reuter, 2012). Independent samples t-tests (Bonferroni-corrected) and multivariate regressions (false discovery rate–corrected) were conducted to assess differences between the cycling and oral contraceptive sessions.
Results:
Global cortical and subcortical gray matter volume decreased (t(57.98) = -4.93, p < .001; t(57.54) = -5.41, p < .001) while average lateral and fourth ventricle size increased with oral contraceptive use (t(52.385) = 4.49 , p < .001; t(57.76) = 3.61, p < .001). Decreases in gray matter volume with oral contraception were observed across the cortex, in areas such as the left medial orbitofrontal, left posterior cingulate, and right supramarginal regions (p < .001 for all), Figure 1. At the subcortical level, most areas similarly demonstrated a decrease in gray matter volume, including bilateral putamen, bilateral caudate, and left hippocampus (p < .001 for all) on hormonal contraception. Two regions bucked the global trend: compared to the naturally cycling state, the left cerebellum and left pallidum had elevated gray matter volume on birth control (p <.001 for both), Figure 2. Global gray matter volume decreased on average by ~0.57% on hormonal contraception. By comparison, global gray matter volume decreased by ~0.63% from morning to evening in a densely-sampled male (Murata, 2024) and by ~4% across a human pregnancy (Pritschet, 2024).
Conclusions:
This series of time-locked, longitudinal, dense-sampling studies offers unique insight into the way the brain responds to hormonal contraception. Future neuroimaging studies are warranted to determine the universality of these findings across individuals and the underlying mechanism. One potential explanation for differences in brain morphology with contraceptive use could be altered states of water retention. Unpublished data from a related dense-sampling study (Heller., In Prep) suggest that these effects are transient, rebounding when the hormonal regimen ends.
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
Cortical Anatomy and Brain Mapping 1
Neuroanatomy Other 2
Keywords:
Cortex
MRI
STRUCTURAL MRI
Sub-Cortical
1|2Indicates the priority used for review
Abstract Information
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2. Lacasse, J. M. (2024). Beyond Birth Control: The Neuroscience of Hormonal Contraceptives. The Journal of neuroscience : the official journal of the Society for Neuroscience, 44(40), e1235242024.
3. Murata, E. M. (2024). Circadian Rhythms Tied to Changes in Brain Morphology in a Densely Sampled Male. The Journal of neuroscience : the official journal of the Society for Neuroscience, 44(38), e0573242024.
4. Pritschet, L. (2024). Neuroanatomical changes observed over the course of a human pregnancy. Nature neuroscience, 27(11), 2253–2260.
5. Pritschet, L. (2021). Applying dense-sampling methods to reveal dynamic endocrine modulation of the nervous system. Current opinion in behavioral sciences, 40, 72–78.
6. Pritschet, L. (2020). Functional reorganization of brain networks across the human menstrual cycle. NeuroImage, 220, 117091.
7. Reuter, M. (2012). Within-subject template estimation for unbiased longitudinal image analysis. NeuroImage, 61(4), 1402–1418.
8. Taylor, C. M. (2021). The scientific body of knowledge - Whose body does it serve? A spotlight on oral contraceptives and women's health factors in neuroimaging. Frontiers in neuroendocrinology, 60, 100874.
9. Taylor, C. M. (2020). Progesterone shapes medial temporal lobe volume across the human menstrual cycle. NeuroImage, 220, 117125.