Imaging the Human Brain on Oral Contraceptives

Abstract

Oral contraceptives (OCs) are the most popular form of birth control in the United States and in European countries. However, little is known about the extent OCs affect the brain’s function and morphology, although it is known that endogenous sex hormones shape the brain across the life span. Here, we reviewed studies that investigated structural gray and white matter in women using OCs in comparison to naturally cycling women. We focused on neuroimaging methods used to quantify structural gray and white matter changes: structural (sMRI) and diffusion MRI (dMRI). Relatively few imaging studies have been performed to answer the question of the effect of OCs on brain architecture. Studies have reported morphometric abnormalities in whole brain, cortical, and subcortical gray and white matter with no consistent pattern. Rather, findings in gray and white matter seem to be dependent on whether women using OCs and naturally cycling women were split into groups (active/inactive intake phase vs. follicular/luteal phase). There is a lack of sMRI and dMRI studies in this field of research. However, current studies demonstrate that it is important to compare women according to the follicular and luteal phase, as well as the active and inactive intake phase of OCs. Future studies with standardized protocols and larger sample sizes will allow an in-depth characterization of the effect of OCs on the brain. Furthermore, longitudinal studies comparing naturally cycling women to women using OCs over time and at different life stages are of particular importance.